Perspectives on Mail-Based Fecal Testing for Colorectal Cancer Screening in Bulgaria: A Survey of Gastroenterologists

Abstract

Background: Bulgaria carries a high burden of colorectal cancer (CRC) but, at the start of this study, lacked a nationwide organized screening program. Understanding specialist views (particularly on mail-based fecal testing) is essential for effective policy development. Objective: The objective is to assess the attitudes towards, practices of, and perceived barriers to CRC screening among Bulgarian gastroenterologists, with a focus on the feasibility of mail-based fecal occult blood testing (FOBT). Methods: A cross-sectional survey of 38 gastroenterologists examined clinical use of FOBT, screening method preferences, and perceived systemic and patient-level barriers to CRC screening. Results: Among respondents, 57.89% reported using FOBT in clinical practice, and 71.05% indicated they would undergo the test themselves and recommend it to relatives. Colonoscopy was the preferred diagnostic tool for 84.21% of participants; however, the existing literature raises concerns about its feasibility for large-scale population screening. Key systemic barriers, rated on a 5-point Likert scale, included financial constraints (mean = 3.08), inadequate infrastructure (2.89), and healthcare workforce shortages (2.71). Patient-level barriers were led by low health literacy (4.13), lack of motivation (3.95), and procedural fears (3.26). A majority (84.38%) believed that mail-based FOBT would increase screening uptake, and 57.89% supported annual distribution of test kits. Nearly all respondents (97.37%) favored initiating screening at age 50. Conclusions: This study highlights strong support among Bulgarian gastroenterologists for a national CRC screening program, with particular endorsement of mail-based FOBT. Despite acknowledged systemic and population-level barriers, the findings suggest that such an approach could increase screening coverage, promote early detection, and support the strategic rollout of Bulgaria’s emerging cancer control initiatives.

1. Introduction

Colorectal cancer (CRC), encompassing malignancies of the colon and rectum, is generally treated as a single clinical entity due to their overlapping characteristics. Its development results from the interplay of non-modifiable biological and modifiable lifestyle-related risk factors [1]. CRC incidence increases with age, placing older adults at a heightened risk. Key contributing factors include physical inactivity, Western dietary patterns, smoking, diabetes, obesity, and ulcerative colitis linked to Helicobacter pylori infection [2].

In 2020, CRC was the third most commonly diagnosed cancer worldwide, following breast and lung cancers, with approximately 1.9 million new cases and an age-standardized incidence rate (ASR) of 19.5 per 100,000 population. Europe recorded the highest regional ASR at 30.4 per 100,000 [3]. Due to frequent diagnosis at advanced stages, CRC remains a leading cause of cancer-related mortality, accounting for nearly 900,000 deaths annually. Systematic screening and treatment advances in high-income countries have significantly reduced both incidence and mortality [4]. In the same year, CRC ranked as the second leading cause of cancer deaths globally (after lung cancer), with approximately 935,000 deaths and an age-standardized mortality rate (ASMR) of 9.0 per 100,000 person–years, and Europe again reported the highest ASMR at 12.3 per 100,000 [3].

CRC poses a significant public health challenge in Bulgaria, ranking among the most commonly diagnosed malignancies and leading causes of cancer-related mortality. According to GLOBOCAN data, an estimated 5086 new CRC cases were diagnosed in 2022, accounting for 15.5% of all new cancer cases—an increase from 4553 cases (12.9%) in 2018. CRC-related mortality also remains high, with 2759 deaths reported in 2022 (14.7% of cancer deaths), up from 2687 deaths (14.0%) in 2018, making it the second leading cause of cancer mortality after lung cancer. Age-standardized rates highlight the national burden: in 2018, the CRC incidence rate was 28.5 per 100,000 and the mortality rate was 14.9 per 100,000—both exceeding the European average reported in 2020. Additionally, the 5-year prevalence increased from 11,751 cases (167 per 100,000) in 2018 to 15,133 cases (221.1 per 100,000) in 2022, underscoring the growing impact of CRC on Bulgaria’s healthcare system [5,6]. Globally, CRC incidence continues to rise, particularly in high-income regions. Notably, there is a growing trend of earlier onset, with an expected increase in cases among individuals under 50 in the coming decade [7,8].

Numerous large-scale studies confirm a substantial reduction in CRC mortality following the introduction of mass screening programs [9]. Population-based screening significantly improves survival by enabling early detection and effective treatment [10]. A study analyzed CRC incidence, mortality, and stage distribution across European countries with varying levels of screening implementation and showed that countries with longstanding, high-coverage programs experienced significant declines in age-standardized incidence, with average annual percent changes ranging from 2.5% to 1.3% across the sexes. In settings where screening coverage expanded rapidly, an initial rise in incidence, attributed to diagnostic anticipation, was followed by a subsequent decline. In contrast, countries lacking organized screening showed steady increases in incidence over time. The study also demonstrated that the greatest reductions in CRC mortality occurred in countries with long-established screening programs, driven by earlier detection and a shift toward localized-stage diagnoses. More recent implementations showed similar trends in stage distribution, while countries without structured screening exhibited minimal changes over time [11].

Additionally, CRC (along with cervical and breast cancers) serves as a key indicator of a healthcare system’s effectiveness in cancer care. Survival rates for these cancers reflect both the capacity for early detection and the quality of treatment delivered. In line with these findings, Gogenur and Qvortrup reported that countries with well-established CRC screening programs, particularly those achieving coverage rates exceeding 50% of the eligible population, demonstrated substantial reductions in CRC incidence [12]. Colorectal, cervical, and breast cancers are widely recognized as key indicators of healthcare system performance, with survival rates reflecting both early detection capabilities and the quality of oncological care [13]. Accordingly, the first European guidelines were introduced in 2010, establishing quality standards for CRC screening and diagnostic procedures. Additionally, the European Parliament’s Resolution of 6 May 2010 urged the European Commission to prioritize comprehensive cancer prevention measures, including the reduction in environmental carcinogenic exposures, and to promote enhanced investment by Member States in screening programs and early diagnosis initiatives.

Despite these efforts, the implementation of CRC screening across Europe has remained inconsistent, with substantial variation in target age groups, screening intervals, and test modalities [9]. Until recently, Bulgaria was one of only four EU countries (alongside Greece, Latvia, and Romania) without an organized national CRC screening program. Screening tests were not reimbursed by the National Health Insurance Fund (NHIF), though colonoscopies were covered when prescribed for symptomatic individuals via primary care referral [14]. In 2024, a pilot CRC screening initiative, led by the Lachezar Tsotsorkov Foundation with support from the Ministry of Health, distributed free fecal immunochemical test (FIT) kits to individuals aged 50–74. Of the 93,218 tests completed, 14.22% yielded positive results. Based on these outcomes, a national CRC screening program is scheduled for launch in autumn 2025 [15,16].

An essential component of successful CRC screening is the selection of an appropriate testing modality, which may involve non-invasive or invasive approaches. CRC can present with rectal bleeding, either overt or occult. Occult bleeding, which is not visible to the naked eye, is detected using stool-based biochemical assays. The two main fecal occult blood tests (FOBTs) used in clinical practice are the guaiac-based FOBT (gFOBT) and the FIT, also known as immunochemical FOBT (iFOBT) [17].

Among the available screening modalities, non-invasive tests such as FIT and gFOBT offer advantages in terms of patient acceptability, safety, and cost, and generally achieve higher uptake than invasive procedures, which can reduce participation by 2–36% [18]. Guaiac-based fecal occult blood tests (gFOBTs) and fecal immunochemical tests FITs are cost-effective non-invasive screening tools for CRC. gFOBT detects heme, while FIT targets human globin and does not require dietary restrictions.

A meta-analysis of four randomized controlled trials found that routine gFOBT screening (annual or biennial) reduces CRC-specific mortality by approximately 16%. FITs offer greater sensitivity for both adenomas and cancers, higher participation rates, and improved detection outcomes. Quantitative FITs allow for adjustable thresholds, enabling adaptation to healthcare system capacity. An ecological study in Italy reported a 22% reduction in CRC mortality in regions implementing FIT-based screening. Modeling studies suggest that repeated high-adherence FIT screening can achieve mortality reductions comparable to colonoscopy.

Colonoscopy remains the gold standard for detecting colorectal neoplasia and is associated with 20–30-year mortality reductions in prospective cohorts. Some programs use it as a primary tool, others adopt a two-step approach, reserving it for follow-up after positive non-invasive tests—improving uptake and reducing strain on limited endoscopic resources. Despite its diagnostic value, a colonoscopy is more invasive and resource-intensive, necessitating careful consideration in national screening policy design [19].

Globally, healthcare systems face mounting pressures due to population aging, the rising prevalence of chronic diseases, and the expansion of population-level screening and surveillance programs. To maintain accessibility, affordability, and quality of care under these conditions, innovative strategies are needed, particularly those that facilitate high screening coverage, as increased cancer screening uptake has been consistently associated with reduced mortality and improved program outcomes [20,21].

Furthermore, choice and rationale of screening modalities must address key barriers to participation, including low health literacy, limited patient motivation, fear of diagnosis or procedures, geographic inaccessibility, cultural stigma, and the perceived burden of colonoscopy. Overcoming these challenges requires screening methods that are user-friendly, acceptable, and accessible, supported by targeted education and system-level interventions [22,23].

Mailed FIT outreach is a multilevel intervention that overcomes structural and behavioral barriers by proactively offering screening outside clinic visits, improving access in remote care settings and reducing provider burden. At the patient level, it enhances convenience and adherence through home-based testing, educational materials, and reminders, making it an efficient, patient-centered strategy to increase CRC screening uptake [24]. Sending FOBT kits directly to individuals (along with instructions, an invitation letter, and a prepaid return envelope addressed to the laboratory) has been shown to significantly boost participation in screening programs [25].

The primary aim of this study was to assess perceptions regarding the implementation of a national CRC screening program based on a mail-distributed fecal occult blood test (FOBT) strategy. Using a structured, web-based survey, the study explored gastroenterologists’ experiences with CRC diagnostics, preferred initial investigations for symptomatic patients, and familiarity with FOBT as a screening tool. It also examined professional views on key logistical aspects of screening implementation, including responsible institutions, optimal screening frequency, and target age groups, as well as perceived system-level and patient-level barriers that may affect participation. The findings are intended to inform national policy discussions and support the design of an effective, accessible, and context-appropriate CRC screening model in Bulgaria.

2. Materials and Methods

2.1. Study Design

A cross-sectional, web-based survey was conducted targeting practicing gastroenterologists in Bulgaria. The survey was administered using the LimeSurvey platform, version 6.15.5. Email addresses of potential participants were collected from publicly available institutional websites of medical universities and healthcare facilities.

A total of 400 invitations were distributed via email. This method was chosen for its efficiency in reaching geographically dispersed specialists and minimizing administrative burden.

Eligible participants included board-certified gastroenterologists and gastroenterology residents with at least one year of clinical experience. This inclusion criterion ensured adequate exposure to clinical decision-making in gastrointestinal screening and encompassed recently graduated physicians. Physicians from other specialties and non-physician healthcare professionals were excluded from the study.

A structured, self-administered questionnaire was developed specifically for this study to assess clinical practices, diagnostic behaviors, and personal views of gastroenterologists regarding CRC screening in Bulgaria.

The questionnaire was designed based on a review of the existing literature and was pilot-tested on a small group of clinicians. The instrument comprised 26 mandatory items, including closed-ended, semi-open, multiple single-choice, and Likert-scale questions, and was administered online in Bulgarian. The questionnaire was organized into three thematic sections: sociodemographic and professional profile of the participants; CRC clinical experience; personal attitudes toward CRC screening.

Participation was entirely voluntary and anonymous, with no incentives offered.

2.2. Statistical Analysis

All statistical analyses were conducted using IBM SPSS Statistics v. 19. Descriptive statistics were employed to summarize participant demographics, clinical practices, and attitudes toward CRC screening. Continuous variables were reported as means with standard deviations (SD). Categorical variables were summarized using frequencies and proportions.

3. Results

3.1. Sociodemographic Characteristics

A total of 38 gastroenterologists participated in the study, corresponding to a response rate of 9.5%. The mean age of participants was 36.45 ± 8.99 years. All participants (n = 38) reported employment in hospital settings, indicating that hospital-based practice was universal within the sample. Additionally, 15 gastroenterologists reported concurrent work in outpatient care settings, suggesting that a notable proportion maintain dual roles across clinical environments. The respondents were distributed across eight cities, with the largest proportion practicing in Plovdiv (44.74%), followed by Sofia (18.42%) and Burgas (15.79%). Smaller numbers of participants were located in Panagyurishte (5.26%), Pleven (5.26%), and Varna (5.26%), while single participants were based in Stara Zagora (2.63%) and Velingrad (2.63%). The detailed sociodemographic and professional characteristics are presented in

Table 1. Sociodemographic and professional characteristics of participants.

Category	Variable	Value
Sex Distribution	Male	21 (55.26%)
	Female	17 (44.74%)
Age (years)	Mean (SD)	36.45 (8.99)
	Median	34.50
	Interquartile Range (IQR)	30.75–40.25
Years of Professional Experience	Mean (SD)	11.04 (9.10)
	Median	8.50
	Interquartile Range (IQR)	5.00–13.25
Practice Setting	Hospital-based practice	38 (100.00%)
	Concurrent outpatient practice	15 (39.47%)

. Sociodemographic and professional characteristics of participants.

3.2. Clinical Experience and Screening Perspectives

Among the 38 gastroenterologists included in the analysis, 57.89% (n = 22) indicated that they had ordered a FOBT in their clinical practice. Conversely, less than half of the participants indicated that they had not ordered the test.

Of those who ordered FOBT, 72.73% (n = 16) cited clinical indications, while 63.64% (n = 14) reported using the test for screening purposes in asymptomatic individuals.

Among the 16 respondents (42.11%) who had not ordered FOBT, reasons were collected through multiple-response options. Concerns regarding test reliability were reported by 66.67% (n = 8), representing 21.05% of the total sample. Additionally, 33.33% (n = 4) indicated the absence of suitable patients as a reason for not ordering the test.

The number of suspected CRC cases managed monthly by the 38 participating gastroenterologists varied substantially. The mean number was 13.92 ± 14.18 cases.

Among the participants, 15.79% (n = 6) managed 5 suspected CRC cases per month, while 13.16% (n = 5) each reported managing 15 or 20 cases. The lowest (0 cases) and highest (80 cases) monthly volumes were each reported by a single respondent (2.63%). More than half of the gastroenterologists reported managing 15 or more suspected CRC cases per month.

When asked about diagnostic tests ordered for patients suspected of CRC, the majority of gastroenterologists (84.21%, n = 32) identified colonoscopy as their primary modality. Occult blood testing was the next most commonly reported investigation (13.16%, n = 5), while a minority (2.63%, n = 1) indicated using alternative diagnostic approaches.

The number of newly diagnosed CRC patients managed monthly by the 38 participants varied considerably. The mean number was 5 ± 5.37 cases per month (range: 1–30).

Among the gastroenterologists who participated in the survey, 26.32% (n = 10) reported managing 10 new CRC cases per month, while an equal proportion (26.32%, n = 10) managed only one case. Additional reported frequencies included five cases (13.16%), four cases (10.53%), three cases (7.89%), and two cases (5.26%). Caseloads of 8, 9, 15, and 30 patients per month were each reported by a single participant (2.63%). Overall, more than half of the respondents reported managing four or more new CRC cases monthly.

Respondents were asked to rate the perceived need for a CRC screening program in Bulgaria on a scale from 1 (lowest need) to 5 (highest need). There was strong consensus regarding the importance of screening: 84.21% (n = 32) assigned the highest score of 5, and 13.16% (n = 5) selected 4. Only one participant (2.63%) rated the need as 1, indicating low perceived necessity.

Participants were also asked to identify the most appropriate screening test for CRC in the Bulgarian context. The majority (68.42%, n = 26) selected colonoscopy as the preferred method. FOBT was chosen by 26.32% (n = 10), while 5.26% (n = 2) were undecided.

Gastroenterologists were asked to assess the importance of several barriers to the implementation of a colorectal cancer screening program in Bulgaria, using a scale ranging from 1 (least important) to 5 (most important). The lack of financial resources was perceived as the most significant barrier, with a mean rating of 3.08 ± 1.50, indicating a moderate level of variability in responses. The lack of infrastructure followed closely, with a mean score of 2.89 ± 1.25. The shortage of healthcare professionals (human resources) received a slightly lower mean rating of 2.71 ± 1.29. The lack of administrative personnel was rated the least important barrier, with a mean score of 2.39 ± 1.31. The data is presented in Figure 1.

Participants evaluated potential factors limiting CRC screening coverage using a 5-point Likert scale (1 = least limiting, 5 = most limiting). The most significant barrier identified was a low level of health culture within the population (mean = 4.13 ± 1.10), followed by lack of patient motivation (mean = 3.95 ± 1.14). Negative perceptions of the healthcare system were also notable (mean = 3.55 ± 1.29).

Fear of receiving a positive result (mean = 3.45 ± 1.22) and fear of the screening procedure (mean = 3.26 ± 1.20) were rated slightly lower. Geographical distance to specialists was perceived as a moderate barrier (mean = 3.21 ± 1.17), while discomfort associated with the screening test was considered the least limiting factor (mean = 3.13 ± 1.14). The data is presented in Figure 2.

Among the 38 gastroenterologists surveyed, 71.05% (n = 27) agreed that a mail-based method for distributing and returning stool sample kits would improve CRC screening coverage in Bulgaria. In contrast, 13.16% (n = 5) disagreed and 15.79% (n = 6) were uncertain. Among the 32 respondents who provided definitive responses, 84.38% (n = 27) supported the mail-based approach, while 15.62% (n = 5) did not.

Regarding its impact on administrative burden, 57.89% (n = 22) of respondents disagreed that the mail-based approach would reduce staff workload, while 28.95% (n = 11) agreed and 13.16% (n = 5) were uncertain.

When asked whether the mail-based method would increase patient convenience, 55.26% (n = 21) responded affirmatively, 23.68% (n = 9) disagreed, and 21.05% (n = 8) were uncertain. Among the 30 respondents who provided a definitive answer, 70.00% (n = 21) indicated the method would enhance convenience, while 30.00% (n = 9) did not.

Among the surveyed gastroenterologists (n = 38), preferences regarding the interval for mailing CRC screening kits varied. The majority (57.89%, n = 22) favored annual distribution, while 26.32% (n = 10) recommended a biennial schedule. Only 5.26% (n = 2) supported a triennial interval, and 10.53% (n = 4) suggested alternative frequencies not included in the predefined options.

Regarding the appropriate age to initiate CRC screening, 97.37% (n = 37) recommended starting above age 50, with only one respondent (2.63%) supporting initiation after age 60. No participants endorsed starting screening at or beyond age 70.

When asked which institutions should be responsible for organizing the mailing of screening kits (multiple responses permitted), 81.58% (n = 31) identified Regional Health Inspections, followed by 47.37% (n = 18) who selected General Practitioners. Municipalities were chosen by 18.42% (n = 7).

Regarding the preferred location for returning completed screening kits, 84.21% (n = 32) favored regional laboratories, while 15.79% (n = 6) preferred a centralized national laboratory.

3.3. Attitudes Toward Personal and Family Use of FOBT

The study evaluated participants’ willingness to undergo FOBT for the early detection of asymptomatic CRC. Among the 38 respondents, 71.05% (n = 27) expressed willingness to participate in screening, while 28.95% (n = 11) were reluctant.

Participants were also asked whether they would recommend FOBT to relatives for early detection of asymptomatic CRC. Identical proportions were observed: 71.05% (n = 27) stated they would recommend the test, while 28.95% (n = 11) would not.

4. Discussion

4.1. Use of FOBT in Clinical Practice

In this study, 57.89% of Bulgarian gastroenterologists reported using FOBT in clinical practice. Among these, 72.73% applied the tests for symptomatic patients (iron-deficiency anemia, abdominal pain, or altered bowel habits) while 63.64% used them to screen asymptomatic individuals. Additionally, 71.1% expressed willingness to undergo FOBT themselves and would recommend it to relatives, reflecting a generally favorable perception of the test.

Extensive evidence supports this favorable view of fecal-based tests in early CRC detection. A systematic review found that biennial guaiac-based FOBT (Hemoccult II) significantly reduced CRC mortality in six large RCTs, with relative risks ranging from 0.91 (95% CI, 0.84–0.98) after 19.5 years to 0.78 (95% CI, 0.65–0.93) at 30 years. Pooled data from nine studies evaluating FIT showed a sensitivity of 74% (95% CI, 64–83%) and specificity of 94% (95% CI, 93–96%) at the standard 20 μg Hb/g feces threshold. Real-world data from over 5 million participants further demonstrated a 10% reduction in CRC mortality following 1–3 rounds of biennial FIT (adjusted RR = 0.90; 95% CI, 0.84–0.95). These findings support the inclusion of FOBT in organized screening programs and aligns with international recommendations that emphasize the value of such tests for both diagnostic and preventive purposes [26,27].

A total of 42.11% of surveyed gastroenterologists reported not using FOBT in clinical practice. Among them, 66.67% cited concerns about test reliability. Additionally, 33.33% reported a lack of suitable patients for fecal testing in their practice. Despite robust evidence supporting FIT for CRC screening, clinician hesitancy persists. This reluctance likely stems from misconceptions about the limitations of earlier tests like gFOBT, underscoring a gap in awareness of updated guidelines. A systematic review confirmed that many healthcare professionals lack adequate knowledge of CRC screening protocols, adversely affecting clinical decision-making. Similarly, Yabroff reported that only 19% of U.S. primary care physicians consistently recommended CRC screening in line with established guidelines [26,28,29,30].

These findings highlight the need for targeted educational initiatives, improved clinical training, and clearer guideline dissemination to enhance provider adherence and optimize the implementation of fecal-based screening programs.

Among respondents, 84.21% identified colonoscopy as their preferred diagnostic test for CRC, followed by FOBT (13.16%), with only one participant (2.63%) selecting alternative methods.

The preference for colonoscopy reflects its status as the gold standard for CRC diagnosis, enabling direct visualization, biopsy, and removal of polyps in a single procedure [31,32]. It demonstrates high diagnostic accuracy, with sensitivity for adenomas ≥10 mm ranging from 89% to 95% (95% CI: 70–99%) and specificity around 89% (95% CI: 86–91%). Sensitivity for CRC detection varies from 18% to 100%, depending on lesion characteristics and study design [33].

Despite its diagnostic advantages, colonoscopy presents several limitations. It is invasive, requires burdensome bowel preparation, and often involves sedation, which can lead to complications. In a cohort of 9962 patients, 180 procedures were discontinued due to preparation-related adverse events [34]. Though rare, colonic perforation remains a serious risk [35], and sedation itself is associated with additional procedural risks [36]. Up to 10% of patients report moderate-to-severe discomfort (including abdominal pain, cramping, and nausea) potentially reducing adherence to future screening [37]. Moreover, gastrointestinal symptoms are nonspecific and often reflect benign conditions. In the absence of rectal bleeding, the probability of CRC is low (1–3%). In such cases, non-invasive testing such as FIT may serve as an effective triage tool, optimizing colonoscopy referrals, particularly in settings with constrained financial resources, healthcare infrastructure, or workforce capacity [38].

4.2. Colorectal Cancer Screening

CRC is among the most frequently diagnosed malignancies and a leading cause of cancer-related mortality in Bulgaria [5,6]. Despite the significant burden of CRC, Bulgaria had not implemented a population-based screening program as of 2023. The European Cancer Inequalities Registry identifies Bulgaria as lacking a national framework and among EU countries with the lowest participation in breast, cervical, and CRC screening. This shortfall persists despite EU recommendations, starting with the 2003 Council Recommendation calling for organized, quality-assured screening programs, particularly using fecal-based tests to promote early detection and reduce mortality [39].

This gap is recognized by medical professionals. In our survey, 84.21% of gastroenterologists rated the need for a national CRC screening program at the highest level (5 out of 5), indicating strong professional consensus on its urgency.

In response to this unmet need, a pilot initiative was launched in 2024 by the Lachezar Tsotsorkov Foundation, in cooperation with the Ministry of Health. The program distributed free FIT to individuals aged 50–74. Of the 93,218 tests completed, 14.22% were positive, demonstrating both the feasibility and the urgent necessity of establishing a structured national program [15].

Building on the success of this pilot, the Bulgarian Ministry of Health has announced the launch of a national CRC program in autumn 2025. The program will offer free FIT kits to individuals aged 45 to 75, which can be completed at home. Test samples will be submitted to accredited laboratories for analysis. The primary goals are early detection and reduction in CRC-related mortality [16]. These efforts align with Bulgaria’s National Cancer Control Plan (2023–2030), which outlines the phased introduction of organized screening programs for major cancer types, including CRC. Effective implementation is expected to enhance early detection, reduce mortality, and improve equity and efficiency in cancer care delivery [14].

When asked to identify the most appropriate screening method, 68.42% of respondents selected colonoscopy, reflecting its recognized diagnostic superiority and status as the clinical gold standard. However, while colonoscopies offer high sensitivity for detecting colorectal neoplasia, the limitations(such as invasiveness, patient discomfort, reliance on trained personnel and infrastructure, and higher costs)raise concerns about its feasibility as a first-line tool in population-based screening programs [31,32,33,34,35,36].

4.3. Barriers to CRC Screening in Bulgaria

This study provides a specialist perspective on the barriers to implementing a national CRC screening program. The findings reveal persistent systemic and population-level challenges that may hinder the effectiveness of organized screening initiatives. Similar patterns have been observed in other Southern European healthcare systems, notably in Greece, where a study identified comparable structural and behavioral obstacles from the perspective of general practitioners [22]. Despite differing clinical roles, both groups reported underinvestment in screening infrastructure, workforce shortages, and limited public sector capacity.

System-level barriers in our study included financial constraints (mean = 3.08), infrastructural deficiencies (mean = 2.89), and personnel shortages (mean = 2.71). These challenges align with those from Greece, where long wait times and limited access to gastroenterology services compromised screening delivery [22]. Persistent underinvestment in infrastructure and human resources continues to impede efforts to establish or expand national CRC screening programs across the region, highlighting the need for substantial organizational and policy support in Bulgaria.

Patient-related barriers were assessed as equally important. Low health literacy (mean = 4.13) and lack of motivation (mean = 3.95) were identified as key obstacles to participation. These concerns reflect those reported by Greek GPs, particularly among older male populations, where fear, stigma, and misinformation impeded engagement with screening [22]. Honein-AbouHaidar similarly reported low public understanding of CRC risk, screening options, and the benefits of early detection. Their systematic review also highlighted common perceptions that screening is unnecessary without symptoms and is often deprioritized due to competing life demands [23].

These findings underscore the critical role of healthcare professionals not only in delivering patient education and counseling, but also in actively shaping perceptions about colorectal cancer screening. Their involvement is essential to building trust, clarifying the purpose and benefits of early detection, and reducing fear and stigma associated with testing. Moreover, these results emphasize the importance of targeted, culturally appropriate communication strategies aimed at improving health literacy, addressing persistent misconceptions, and promoting CRC screening as a routine and accepted element of preventive healthcare.

Fear-related barriers, specifically fear of a positive result (mean = 3.45) and fear of the test itself (mean = 3.26), were identified as moderately significant by respondents. These findings align with those of Ploukou et al., who reported that anxiety related to colonoscopy, including concerns about discomfort and diagnosis, frequently discouraged patient participation [22]. Similarly, Honein-AbouHaidar described fear as a multilevel barrier including fear of cancer, diagnosis, and subsequent suffering. Their review also highlighted the perception of colonoscopy as invasive and unpleasant, with apprehensions about bowel preparation, procedural pain, and potential complications such as perforation contributing to avoidance behavior [23].

These insights suggest that interventions to reduce fear should focus on empathetic communication by healthcare professionals, providing patients with detailed yet reassuring information about the safety and tolerability of procedures, and offering pre-procedural counseling or support services. Tailored educational materials that demystify CRC and clarify its role in prevention could further mitigate anxiety and promote greater acceptance of screening.

Geographic accessibility emerged as a moderate barrier in our study (mean = 3.21), reflecting challenges in reaching specialized care. Similar difficulties were reported in Greece, where patients in remote areas faced long travel distances and limited transport options. These logistical barriers disproportionately affect vulnerable populations and contribute to inequities in screening uptake [22]. Although colonoscopy was the preferred screening method among our respondents, its invasive nature, procedural demands, and reliance on specialized resources limit its suitability for large-scale application. Both our findings and those of Ploukou indicate that a colonoscopy is often reserved for symptomatic individuals or those with family history, rather than used systematically for prevention [22].

4.4. Feasibility of Mail-Based FOBT Distribution

Even though a colonoscopy is considered the clinically optimal method for CRC screening, its invasive nature, procedural complexity, and limited accessibility may restrict its suitability for large-scale population screening. These limitations can reduce overall screening coverage, a critical factor for the success of any national program. Higher coverage rates are consistently associated with lower cancer mortality and improved program effectiveness [21,40]. Therefore, alternative or complementary screening strategies should be considered, particularly those that are less invasive, more accessible, and better aligned with patient preferences. In December 2022, the Council of the European Union issued updated recommendations on cancer prevention, replacing the 2003 guidelines. The new framework emphasizes evidence-based, risk-adapted screening and designates quantitative FIT as the preferred method for individuals aged 50 to 74. Endoscopic procedures may also be employed within integrated or follow-up screening pathways [41].

A strategy which could overcome the barriers to high screen coverage is the mail-based distribution of FOBT kits. Mailed FIT outreach is a multicomponent intervention that addresses structural and behavioral barriers across the care continuum. At the system level, it expands reach by offering screening independent of clinic visits-particularly relevant in remote or telehealth-driven settings. For providers, it reduces time pressures during consultations and supports streamlined follow-up. At the patient level, it enhances accessibility through home-based testing, educational materials, reminders, and, where available, navigation support. This integrated, patient-centered approach has proven effective in increasing CRC screening uptake [24].

When asked about the feasibility of mailing stool collection kits in Bulgaria, respondents were evenly divided (50% yes, 50% no). However, among those who provided a definitive opinion, 84.38% believed the approach would improve screening uptake. Similarly, 70% agreed that it would enhance patient convenience, suggesting broad support for its practical benefits.

These findings are consistent with broader evidence. A meta-analysis showed that mailed outreach for stool-based CRC screening led to a 28% absolute increase in uptake compared to usual care (95% CI: 25–30%; I² = 47%). Subgroup analyses confirmed comparable effectiveness across test types, with a 27% increase for FIT (95% CI: 23–31%; I² = 67%) and 28% for gFOBT. These results strongly support mailed outreach as an effective, scalable strategy, particularly in contexts where opportunistic screening is underutilized [42].

Building on existing evidence, Goodwin et al. conducted a systematic review and meta-analysis that identified four key strategies that significantly improve participation in mailed FOBT programs: advance notification, GP endorsement, telephone contact, and simplified testing procedures. Live telephone reminders were most effective (RR = 1.23; 95% CI: 1.08–1.40), while automated calls showed no impact. GP endorsement, especially with personally signed letters, was linked to increased uptake (RR = 1.01–2.19), with practice-issued letters also effective at select time points. Advance letters, typically sent two weeks before kit delivery, produced modest but consistent gains (RR = 1.06–1.22). Simplifying test procedures (e.g., using FIT kits with fewer steps and no dietary restrictions) further enhanced return rates, outperforming add-ons like stool collection aids. Other methods had mixed results. Implementation intention techniques (e.g., “if-then” planning) had a small but significant effect (RR = 1.05; CI: 1.04–1.07), whereas strategies invoking regret or social influence were ineffective. Most print materials failed to boost uptake, though simplified leaflets with CRC education showed a modest benefit (RR = 1.12; CI: 1.01–1.23); narrative formats and overly detailed materials were occasionally counterproductive [43]. Furthermore, a randomized population-based study conducted in Latvia by Santare et al. demonstrated the influence of invitation strategy and test selection on CRC screening participation. All invitees received a mailed kit including a test, instructions, and prepaid return envelope, an approach that facilitated engagement. Participation was significantly higher with FIT, at 47.4% for OC-Sensor and 44.7% for FOB Gold, compared to 31.2% for gFOBT, likely due to FIT’s ease of use (single sample, no dietary restrictions). Reminder letters sent to non-responders led to 30.9% of returns, while advance notifications increased overall participation by 3.1%, with the greatest effect seen in the gFOBT group (+7.7%). These findings emphasize that combining mailed invitations with simplified tests, advance notifications, and reminders can markedly improve screening uptake [25].

A microsimulation study demonstrated the cost-effectiveness of mailing FIT for CRC screening in France. Using the MISCAN-Colon model for individuals aged 35+, the study found that mailing FIT kits (compared to GP collection) could reduce CRC mortality by 6% and incidence by 3%, with an incremental cost-effectiveness ratio (ICER) of EUR2149 per QALY gained, assuming a 45% participation rate [44].

4.5. Lessons from Successful International Mail-Based FOBT Programs

Given the demonstrated advantages of mail-based testing, many countries have adopted this approach as a key element of their national colorectal cancer (CRC) screening programs. The NHS Bowel Cancer Screening Programme in England exemplifies this approach: established in 2006, it initially targeted individuals aged 60–69, later expanding to 70–74, and began lowering the eligibility age to 50 in 2021, with full rollout anticipated by 2025. The program employs a home-based fecal testing kit, mailed directly to eligible individuals registered with general practitioners, with completed tests returned by post. The transition from guaiac-based FOBT (gFOBT) to the more sensitive fecal immunochemical test (FIT) in 2019 improved participation, reflecting the importance of aligning screening tools with user preferences and technological advances. Importantly, abnormal results trigger colonoscopy referral, enabling timely intervention. To support participation, the NHS also operates a telephone helpline, a seemingly minor but crucial feature that helps sustain public engagement and trust by offering guidance and reassurance during the screening process [45].

A study published in August 2023 reported a nearly 7% reduction in CRC incidence among screening-age adults in England following the introduction of the national bowel cancer screening program. As this estimate predates the full implementation of FIT, which replaced guaiac-based testing in 2019, the actual decline may be greater. Between April 2023 and March 2024, nearly 7 million individuals were invited to participate, achieving a 67.6% uptake rate. Among those screened, 1.76% required further investigation, resulting in over 35,000 colonoscopies that detected at least one high-risk polyp and identified over 5300 cases of CRC (0.11% detection rate). The program also demonstrated high specificity, with only two false positives per 1000 screened [46].

Australia’s National Bowel Cancer Screening Program (NBCSP) similarly demonstrates that mail-based approaches can achieve national scale and significant coverage by sending free FIT kits accompanied by instructions and prepaid return envelopes [47]. The Netherlands adopted a phased approach from 2014 to 2019, offering biennial FIT screening for individuals aged 55–75, using a positivity threshold of 47 μg Hb/g feces to guide colonoscopy referral. Participation rates consistently exceeded 70%, with approximately 85% of those with positive tests completing a follow-up colonoscopy, demonstrating that clarity of procedure and robust organization can maintain patient engagement over time [48].

Denmark’s experience reinforces these lessons. Its FIT-based CRC screening program, launched in 2014 and operating biennially since 2018, provides screening at no charge within a tax-funded system. Participants aged 50–74 receive mailed invitations, an information leaflet, and an FIT kit with an OC Sensor device. A positive test (≥20 µg Hb/g feces) leads to a colonoscopy within two weeks, ensuring prompt diagnostic follow-up [49,50]. Pre-pandemic participation stood at 60.7%, and adherence to follow-up remained strong despite COVID-19-related disruptions. The resilience of this program highlights the importance of administrative preparedness and participant-friendly logistics [51].

The insights from these international examples provide several actionable lessons for Bulgaria. There is strong evidence that mailed FIT programs effectively overcome common participation barriers, including geographic inaccessibility, limited patient engagement and competing time demands, and most importantly achieve high participation rates. These findings are consistent with the present study, in which 84.38% of Bulgarian gastroenterologists endorsed mail-based FIT as a strategy likely to improve screening uptake. And consistent with expert guidance, 57.89% of gastroenterologists surveyed supported an annual interval for mailing CRC screening kits [52].

However, while most respondents recognized the convenience and reach of mail-based FIT, a majority (57.89%) expressed skepticism that it would reduce administrative workload. This suggests that operational planning must explicitly address the integration of logistics, tracking, and laboratory processes to avoid shifting burdens from clinical practice to administrative systems. Close coordination between healthcare providers, laboratories, and regional health structures will therefore be critical for smooth implementation.

Nearly all Bulgarian gastroenterologists (97.37%) identified age 50 as the appropriate threshold for initiating CRC screening, aligning with NHS [53] and European [54] guidelines. In contrast, Bulgaria’s forthcoming national program plans to lower this threshold to 45 years [16], reflecting recent epidemiological evidence of increasing early-onset CRC incidence globally [8]. This should be accompanied by targeted information and outreach strategies for individuals aged 45–49, a group not traditionally included in screening programs but increasingly recognized as at elevated risk.

A clear preference for decentralized laboratory processing emerged among surveyed gastroenterologists, with 84.21% supporting the return of CRC screening samples to regional laboratories, compared to only 15.79% who favored centralization to a single national facility. This inclination likely reflects practical advantages associated with decentralized models-such as faster turnaround times, enhanced logistical feasibility, and closer integration with regional healthcare infrastructure. Moreover, decentralized processing may improve responsiveness and reduce delays in communicating results, which is essential for sustaining participant engagement and trust in population-based screening programs. These findings underscore the need to align laboratory infrastructure with clinical stakeholder expectations to ensure timely, efficient, and scalable implementation.

International experience confirms that mail-based FIT programs are feasible and effective when underpinned by patient-centered logistics, clear communication strategies, timely diagnostic follow-up, and strong laboratory infrastructure. For Bulgaria, successful implementation will depend on ensuring adequate regional laboratory capacity to manage increased testing volumes efficiently and to minimize delays in result reporting. Reminder systems [55], such as advance notifications and follow-up messages, combined with a clearly stated deadline for kit return in the invitation letter [56], should be integrated into the program design to maximize participation rates. General practitioners play an important role in promoting screening and addressing patient hesitancy; therefore, their active engagement and endorsement are critical for success. In parallel, accessible patient support services (such as telephone helplines) will be essential to guide individuals through the screening process, particularly those with limited health literacy or unfamiliarity with home-based testing. Close coordination between healthcare providers, laboratories, and regional health authorities will be required to streamline workflows and prevent unnecessary administrative burdens. The experiences of England, the Netherlands, Denmark, and Australia demonstrate that when these conditions are met, mail-based FIT programs can achieve high participation rates, promote early detection, and reduce colorectal cancer mortality. Bulgaria’s forthcoming program should integrate these lessons, while also tailoring communication and outreach efforts to effectively engage individuals.

4.6. Limitations

This study presents valuable insights regarding the implementation of a national CRC screening program in Bulgaria. However, several limitations should be acknowledged. First, the sample size was relatively small (n = 38) and does not allow for reliable inferential statistical analysis. Additionally, although participants were selected for their clinical relevance and expertise, the findings may not fully represent the broader perspectives of healthcare professionals involved in CRC prevention, such as general practitioners, nurses, or health system administrators. Including these stakeholders could have provided a more comprehensive understanding of implementation barriers and facilitators.

Second, the survey relied on self-reported perceptions, which may be subject to response and recall bias. Participants may have over- or under-estimated the feasibility and impact of certain interventions, such as mailed FIT distribution based on personal experience or institutional context rather than empirical performance data. Moreover, while the study gathered opinions on multiple logistical and systemic issues (e.g., test return infrastructure, administrative workload, decentralization), it did not independently verify the operational capacity of regional laboratories or existing administrative systems.

Third, the survey assessed acceptability and perceived impact of specific strategies, but did not evaluate actual behavioral outcomes, such as changes in clinical practice or patient participation. As such, the study provides preliminary guidance rather than conclusive evidence on implementation effectiveness.

Furthermore, the sample was skewed toward younger professionals (mean age 36.45 years), which may have influenced attitudes toward novel approaches such as mail-based screening, as younger specialists may be more receptive to innovation. This demographic profile may therefore limit the generalizability of the findings to the entire gastroenterology workforce.

Finally, the external validity of the findings may be limited by Bulgaria’s unique healthcare structure, funding mechanisms, and population health literacy levels. Although comparisons were drawn with programs in other European countries, the applicability of international evidence to the Bulgarian context should be interpreted with caution, particularly considering infrastructural disparities and historical underinvestment in preventive services.

Future research should involve broader, multi-professional cohorts and consider mixed-methods approaches to triangulate perceived barriers with operational realities and patient-level outcomes.

5. Conclusions

This study reveals a strong level of support from Bulgarian gastroenterologists for a national CRC screening program, with particular endorsement of mail-based FOBT as a feasible strategy. Despite recognized systemic and population-level barriers, the findings suggest that such an approach could enhance screening coverage, improve early detection, and guide strategic implementation within Bulgaria’s emerging cancer control framework.