Comparison of Tumor Diameter and Tumor Volume in Terms of Aggressive Tumor Behavior and Prognosis in Papillary Thyroid Cancer

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comparison of tumor diameter and tumor volume in terms of aggressive tumor behavior and prognosis in papillary thyroid cancer

The authors used data from patients with single foci papillary thyroid cancer and investigated the relationship between tumor diameter and tumor volume and the aggressive features and prognosis of the disease. They found no significant difference between tumor diameter or tumor volume and any of the features tested except for the lymph node metastasis, which was a negative correlation with tumor volume in a subset of their data. The manuscript is well-written, and the data is clearly presented. I have very few minor comments.

 

Line 60 – 61 & line 73: “tumor size”: Why not to call it tumor diameter? less confusing and is also consistent with the rest of the manuscript?

Line 61: why only 3 thresholds are mentioned for the 4 stages. Please clarify.

Table 1: The numbers in front of “tumor diameter” & “tumor volume” are hard to follow (not aligned with the text).

Line 221: What is V1a. Is this a typo?

The conclusion section misses mentioning the main finding of the manuscript (the negative correlation between TV and LNM)

Author Response

Comments and Suggestions for Authors

Comparison of tumor diameter and tumor volume in terms of aggressive tumor behavior and prognosis in papillary thyroid cancer

The authors used data from patients with single foci papillary thyroid cancer and investigated the relationship between tumor diameter and tumor volume and the aggressive features and prognosis of the disease. They found no significant difference between tumor diameter or tumor volume and any of the features tested except for the lymph node metastasis, which was a negative correlation with tumor volume in a subset of their data. The manuscript is well-written, and the data is clearly presented. I have very few minor comments.

Comments 1: Line 60 – 61 & line 73: “tumor size”: Why not to call it tumor diameter? less confusing and is also consistent with the rest of the manuscript?

Response 1: We sincerely appreciate your efforts and valuable contributions to the review of our article. Throughout the entire article and when presenting our own data, we preferred to use 'tumor diameter' instead of 'tumor size.' We also replaced 'size' with 'diameter' in the lines you pointed out. However, in the sentence referring to the TNM classification, we left 'size' as it appears in the original classification (line60-61) (source: Lamartina L, Grani G, Arvat E, Nervo A, Zatelli MC, Rossi R, Puxeddu E, Morelli S, Torlontano M, Massa M, Bellantone R, Pontecorvi A, Montesano T, Pagano L, Daniele L, Fugazzola L, Ceresini G, Bruno R, Rossetto R, Tumino S, Centanni M, Meringolo D, Castagna MG, Salvatore D, Nicolucci A, Lucisano G, Filetti S, Durante C. 8th edition of the AJCC/TNM staging system of thyroid cancer: what to expect (ITCO#2). Endocr Relat Cancer. 2018 Mar;25(3):L7-L11).

Comments 2: Line 61: why only 3 thresholds are mentioned for the 4 stages. Please clarify.,

Response 2 :According to yoıur recommendation we changed the sentence “In this system, tumors are classifed as T1a, T1b, T2 and T3a according to tumor size with thresholds of 1, 2 and 4 cm. “ as “In this system, tumors are classifed as T1a, T1b, T2 and T3a according to tumor size as ≤1cm, > 1 cm and ≤2 cm, >2 cm and ≤4 cm, and >4 cm, respectively.

 

Comments 3: Table 1: The numbers in front of “tumor diameter” & “tumor volume” are hard to follow (not aligned with the text).

Response 3 :Dear Editor, the table has been revised and added to the text, Thank you

Comments 4: Line 221: What is V1a. Is this a typo?

Response 4 :Dear Editor, yes, as you suggested, it was typographical error and corrected as “T1a”.

Comments 5: The conclusion section misses mentioning the main finding of the manuscript (the negative correlation between TV and LNM)

Response 5 :We added ‘’In our study, although no significant association was found between TD and aggressive tumor characteristics, a significant inverse relationship was observed between LNM and TV in patients with a TD > 2 cm’’ to conclusions. Thank you for your valuable insights.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for your study regarding a very interesting issue

The limitations you do mention 

1. inclusion of PTC only
2. the fact that lymph node dissection is not routinely performed in your center
3. ellipsoid volume formula is ideal for tumors having spherical shapes, however it might be less accurate in tumors that are mostly irregular 

may affect your results as possible bias. Neverthelss, you have studied a homogenous group of thyroid cancer patients in order to investigate how Tumor Volume vs Tumor Diameter affects prognosis and thus therapeutic management. Inclusion of other Differentiated Thyroid Cancer subtypes alongside tumor molecular characteristics would be of great interest. 

Author Response

 

ROUND 2

 

Comments and Suggestions for Authors

Thank you for your study regarding a very interesting issue

The limitations you do mention 

1. Comments 1: inclusion of PTC only

 

Response 1: We conducted this study by analyzing data from 7,000 (benign and malignant) patients who underwent thyroidectomy. To create a unique and homogeneous group, we focused exclusively on papillary thyroid cancers, as the dissemination behaviors of papillary and follicular thyroid cancers can differ.

 

 

 

1. Comments 2: the fact that lymph node dissection is not routinely performed in your center

 

Response 2 :Dear reviewer, you have touched upon a discussion that has been ongoing for years. The indications for prophylactic central lymph node dissection are still controversial , the leading treatment guidelines are not concordant regarding the application of prophylactic central lymph node dissection. American Thyroid Association (ATA) guidelines recommend that routine prophylactic central lymph node dissection should be performed only in patients with advanced T3 and T4 primary tumors. However, this may not be appropriate as many T1 or T2 tumors also exhibit CLNM, and different clinicopathologic parameters may play crucial roles in CLNM (1). The European Society of Endocrine Surgeons suggests that prophylactic central neck dissection should be risk-stratified(2). The potential risk factors include large tumors (T3 or T4), age ≥ 45 years or ≤ 15 years, male sex, bilaterality or multifocality, and involvement of lateral lymph nodes (3). The Chinese Association of Thyroid Oncology and Chinese Anti-Cancer Association recommends prophylactic central lymph node dissection for cN0 PTMC patients (4) The Japanese Association of Endocrine Surgeons(JAES) routinely recommends prophylactic central lymph node dissection. This may be attributed to the fact that the use of radioactive iodine is limited due to legal restrictions (5).

Some authors recommend routine central lymph node dissection in order to prevent future recurrence, citing the high risk of positive lymph nodes, reduced postoperative thyroglobulin (Tg) levels, and a lower morbidity rate associated with the first operation, whereas others suggest that this procedure increases the risk of injury to parathyroid glands and recurrent laryngeal nerves, without any demonstrable benefits in terms of long-term survival. To decrease the risk of postoperative complications related to prophylactic central lymph node dissection, unilateral central lymph node dissection has emerged as an alternative approach to bilateral central lymph node dissection. Ipsilateral central lymph node dissection appears to be a safe, and efficious alternative to bilateral central lymph node dissection, but no conclusive data are available. Therefore, preoperative identification of patients with PTC at greater risk of metastases to the central compartment would be valuable (6).

 

The above examples can be further reproduced. There are many studies for and against the concept of prophylactic central compartment dissection. The feasibility of prospective studies on microcarcinoma outcome is low because PTCs would require decades of follow-up due to the indolent behavior of these tumors. The future molecular characterization of PTC biology should overcome the uncertainty regarding the risk of progression and, consequently, will better indicate the most appropriate treatment for PTCs in terms of cost/benefit.  Prophylactic central neck dissection is a controversial procedure and should only be performed selectively in high-risk patients.

Another crucial aspect is the detection of suspicious lymph nodes in the preoperative period, where ultrasound stands out as our primary imaging tool.

Ultrasonography is the most effective and convenient preoperative thyroid examination. Metastatic lymph nodes are often round in shape, with loss of fatty hilum, calcification in the cortex, cystic changes, hypoechogenicity, and peripheral vascularity. However, it is very difficult to achieve a satisfactory rate of diagnosis prior to surgery because the exploration of central lymph nodes is significantly affected by glands, bones, and gas. Several studies reported that the sensitivity of ultrasonography in identifying central lymph node metastases was quite low. Yu et al reported that less than 30% of central lymph node metastases confirmed by frozen section in patients with PTMC could be diagnosed by preoperative ultrasonography (7). In a review and metaanalysis by Sun et al, neck ultrasonography and contrast enhanced computed tomography were not particularly accurate for preoperative imaging to visualize the metastatic central lymph node lesions (sensitivities of 23%-53.2% and 41%- 66.7%, respectively) (1).

We perform thyroid/neck ultrasonography in all patients with thyroid nodules or thyroid cancer in our center. We did not include this data in our study both due to the above-mentioned conditions. and the possible inter and intraobserver variations related with the fact that different physicians are performing ultrasonography in our center

1.Sun W, Lan X, Zhang H, et al. Risk factors for central lymph node metastasis in CN0 papillary thyroid carcinoma: a systematic review and meta-analysis. PLoS One. 2015;10(10):e0139021

2.Mazzaferri EL, Kloos RT. Clinical review 128: current approaches to primary therapy for papillary and follicular thyroid cancer. J Clin Endocrinol Metab 2001;86:1447–63.

3. Sancho JJ, Lennard TW, Paunovic I, Triponez F, Sitges-Serra A. Prophylactic central neck disection in papillary thyroid cancer: a consensus report of the European Society of Endocrine Surgeons (ESES). Langenbecks Arch Surg 2014; 399: 155-163
4. Gao M, Ge M, Ji Q, Cheng R, Lu H, Guan H, Gao L, Guo Z, Huang T, Huang X, Li X, Lin Y, Liu Q, Ni X, Pan Y, Qin J, Shan Z, Sun H, Wang X, Xu Z, Yu Y, Zhao D, Zhang N, Zhang S, Zheng Y, Zhu J, Li D, Zheng X, Chinese Association Of Thyroid Oncology Cato Chinese Anti-Cancer Association. 2016 Chinese expert consensus and guidelines for the diagnosis and treatment of papillary thyroid microcarcinoma. Cancer Biol Med 2017; 14: 203-211

5.Takami H, Ito Y, Okamoto T, Yoshida A. Therapeutic strategy for differentiated thyroid carcinoma inJapan based on a newly established guideline managed by Japanese Society of Thyroid Surgeons andJapanese Association of Endocrine Surgeons. World J Surg. 2011; 35: 111–121.

6.Qu H, Sun GR, Liu Y, He QS. Clinical risk factors for central lymph node metastasis in papillary thyroid carcinoma: a systematic review and meta-analysis. Clin Endocrinol (Oxf). 2015;83(1):124–132.

7.Yu X, Song X, Sun W, Zhao S, Zhao J, Wang YG. Independent Risk Factors Predicting Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma. Horm Metab Res 2017; 49: 201-207

 

 

 

 

 

 

1. Response 3:Comments 3:ellipsoid volume formula is ideal for tumors having spherical shapes, however it might be less accurate in tumors that are mostly irregular 

 

 

 

 

According to your recommendation we changed the sentence’’ ellipsoid volume formula is ideal for tumors having spherical shapes, however it might be less accurate in tumors that are mostly irregular’’in discussion to ‘’The formula we have preferred, as proposed in the literature, facilitates volumetric calculations based on imaging data and provides comparable results. Although this ellipsoid volume formula is ideal for tumors with spherical shapes, it may be less accrate in tumors that are mostly irregular’’ Thank you for your valuable insights.

 

 

 

Thank you very much for your valuable comments and suggestions. We hope that the responses we provided have been sufficient and satisfactory. As you pointed out, we would like to mention that your insights have broadened our perspective for larger-scale studies that include other types of thyroid cancer and incorporate the evaluation of molecular markers.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This study explores tumor diameter (TD) and tumor volume (TV) in single-foci papillary thyroid cancer, addressing a gap in multifocal-focused literature. The results could have merit in the related field if the authors addressed the following major concerns.

General comment

The manuscript should be updated with recent references. Most citations were >5-10 years ago. Just as examples among others:

- Oh HS, Kwon H, Song E, et al. Tumor Volume Doubling Time in Active Surveillance of Papillary Thyroid Carcinoma.Thyroid 2019. DOI: 10.1089/thy.2018.0609

- Jiang KC, Lin B, Zhang Y, Zhao LQ, Luo DC. Total tumor diameter is a better indicator of multifocal papillary thyroid microcarcinoma: A propensity score matching analysis. Front Endocrinol (Lausanne). 2022;13:974755. Published 2022 Aug 8. doi:10.3389/fendo.2022.974755

- Can, N.; Bulbul, B.Y.; Ozyilmaz, F.; Sut, N.; Mercan, M.A.; Andaç, B.; Celik, M.; Tastekin, E.; Guldiken, S.; Sezer, Y.A.; et al. The Impact of Total Tumor Diameter on Lymph Node Metastasis and Tumor Recurrence in Papillary Thyroid Carcinomas. Diagnostics 2024, 14, 272. https://doi.org/10.3390/diagnostics140

 

1- Introduction: There are limited citations of existing studies on TV in thyroid cancer. The authors should acknowledge imaging-based TV research (e.g., ultrasound or CT-derived volumes) and explain why pathological TV might differ.

2-The clinical implications of the current study were not clear. The introduction does not clarify how TV could refine existing staging systems (e.g., AJCC/ATA). Could TV thresholds redefine T categories or influence surgical planning?

3- While the ellipsoid formula is mentioned, variability in TV calculation methods (e.g., segmentation vs. mathematical models) is not addressed. The authors should justify the choice of the ellipsoid formula and acknowledge potential limitations (e.g., irregular tumor shapes).

4- The negative TV/LNM association in PTC contrasts with positive correlations in other cancers. This paradoxical finding needs preliminary exploration (e.g., cystic vs. solid morphology). The authors could hypothesize biological reasons (e.g., cystic tumors having lower metastatic potential despite larger volumes) to frame the study’s unique contribution.

5- Only 118/3000 patients were included in this study due to missing 3D measurements in pathology reports. This risks selection bias (e.g., larger/more aggressive tumors may have had dimensions recorded). The authors should compare demographics (age, sex, tumor stage) between included/excluded cohorts to assess this bias.

6-  While π/6 (~0.523) is widely used, current literature proposes 0.529 as optimal. The 1.1% discrepancy could affect volume accuracy. Please, justify π/6 with citations or validate using 0.529 in sensitivity analysis.

7- Non-routine CLND may under-detect LNM, skewing associations between TV/LNM. The authors should acknowledge this limitation and stratify analysis by dissection extent (e.g., CLND performed vs. not).

8- The authors should report inter-observer concordance for tumor measurements or cite prior validation studies.

9- There was no adjustment for confounders (age, sex, BRAF) in logistic regression models. Current literature found age could significantly impact TV-LVI associations. It is highly recommended that the authors perform multivariate analysis adjusting for age, sex, and lymphocytic thyroiditis.

10- As only 31 patients had tumors >2 cm, limiting the reliability of the TV-LNM association, the authors should acknowledge the low power and validate findings in a larger cohort.

11- Wide confidence intervals in multivariate analyses suggest instability in estimates.

12- The authors can consider additional analyses stratified by age groups (e.g. <55 vs ≥55 years).

13- Also, the authors can include sensitivity analyses to test the robustness of the findings.

14- Discussion: The inverse relationship between tumor volume and lymph node metastasis in tumors >2cm is not adequately explained. More hypotheses or potential biological mechanisms should be explored.

15- The discussion could benefit from more specific suggestions for future research to address the study's limitations and unexpected findings.

16- While limitations are discussed, they could be more critically analyzed in terms of their impact on the study's conclusions.

17- The small sample size, particularly for tumors >2cm, is a significant limitation that warrants more discussion regarding its impact on the reliability of the findings.

Author Response

Comments and Suggestions for Authors

This study explores tumor diameter (TD) and tumor volume (TV) in single-foci papillary thyroid cancer, addressing a gap in multifocal-focused literature. The results could have merit in the related field if the authors addressed the following major concerns.

General comment

The manuscript should be updated with recent references. Most citations were >5-10 years ago. Just as examples among others:

- Oh HS, Kwon H, Song E, et al. Tumor Volume Doubling Time in Active Surveillance of Papillary Thyroid Carcinoma.Thyroid 2019. DOI: 10.1089/thy.2018.0609

- Jiang KC, Lin B, Zhang Y, Zhao LQ, Luo DC. Total tumor diameter is a better indicator of multifocal papillary thyroid microcarcinoma: A propensity score matching analysis. Front Endocrinol (Lausanne). 2022;13:974755. Published 2022 Aug 8. doi:10.3389/fendo.2022.974755

- Can, N.; Bulbul, B.Y.; Ozyilmaz, F.; Sut, N.; Mercan, M.A.; Andaç, B.; Celik, M.; Tastekin, E.; Guldiken, S.; Sezer, Y.A.; et al. The Impact of Total Tumor Diameter on Lymph Node Metastasis and Tumor Recurrence in Papillary Thyroid Carcinomas. Diagnostics 2024, 14, 272. https://doi.org/10.3390/diagnostics140

 

The references have been added to the text. Thank you for your valuable feedback 

Comments 1:

• Introduction: There are limited citations of existing studies on TV in thyroid cancer. The authors should acknowledge imaging-based TV research (e.g., ultrasound or CT-derived volumes) and explain why pathological TV might differ.

Response 1:  Yes, you are correct. There can be a difference between the size measured by preoperative thyroid ultrasound (US) and the postoperative histopathological size. It’s important to consider a few key points regarding this discrepancy:

Primarily, US measurements can often lead to overestimation of tumor size. Factors such as marginal irregularity and the presence of a peripheral halo have been associated with overestimating the actual tumor size. Sowerby et al. demonstrated that US measurements were, on average, 0.54 cm larger than pathological measurements in 263 benign and malignant thyroid nodules (1). Similarly, Bachar et al. found that the discrepancy between US and pathological measurements was significant only for nodules larger than 15 mm (2). A study that categorized thyroid nodules based on their US diameter found an overall concordance rate of 45.7%, with the highest concordance (78.5%) seen for 1 cm nodules and the lowest (34.5%) for those between 2.1-3 cm (3).

Several factors contribute to the differences between US and histopathological measurements. These can be grouped into three categories: US-related factors, histopathological factors, and time-related factors.

1. US-related factors: Ultrasound is an operator-dependent technique, meaning variability between different observers can influence measurement accuracy. Brauer et al. reported a 16% interobserver variability in determining the maximum nodule diameter (4).
2. Histopathological factors: The method of slicing the specimen can impact tumor size measurement in pathology. The standard practice of making 5 mm axial slices can result in an underestimation of tumor size if the nodule is positioned obliquely. This issue can be mitigated by making oblique cuts. Additionally, US measurements are done in-vivo, while histopathological measurements are in-vitro. The tumor can shrink after surgical removal due to devascularization, leading to smaller measurements in histopathology compared to ultrasound.
3. Time-related factors: The size and structure of the nodule can change between the time of the ultrasound and surgery. For instance, preoperative fine needle aspiration biopsy (FNAB) can reduce nodule size due to hemorrhage, infarction, or scarring (5).

Our primary concern was the lack of interobserver and intraobserver variability data for ultrasound measurements. Due to this and the potential discrepancies mentioned above, we could not rely on preoperative ultrasound data for our study.Regarding tumor size measurement in thyroidectomy specimens, the three-dimensional diameter of the tumor is determined during macroscopic evaluation of fresh tissue before formalin fixation.

We added ‘Even though there is factors might influence the measurements should be considered while comparing nodule diameter in US and tumor size in histopathology (due to that US is an operator dependent method, method of slicing the specimen and size and structure of the nodule can change between the time of the ultrasound and surgery), thyroid ultrasound remains useful for surgical decision-making and avoiding unnecessary surgeries.), thyroid ultrasound remains useful for surgical decision-making and avoiding unnecessary surgeries.’’  Thank you for your valuable insights

 

 

Comments 2:

2-The clinical implications of the current study were not clear. The introduction does not clarify how TV could refine existing staging systems (e.g., AJCC/ATA). Could TV thresholds redefine T categories or influence surgical planning?

Response 2:  You are right about this issue. To our knowledge, there is no study examining the relationship between TV, calculated using histopathologically determined TDs, and tumor behavior in PTC. In our study, although no significant association was found between TD and aggressive tumor characteristics, a significant inverse relationship was observed between LNM and TV in patients with a TD > 2 cm. With this results of our study, we would like to make further research by collecting more data to examining how TV could refine existing staging systems (e.g., AJCC/ATA).

Comments 3:

3-While the ellipsoid formula is mentioned, variability in TV calculation methods (e.g., segmentation vs. mathematical models) is not addressed. The authors should justify the choice of the ellipsoid formula and acknowledge potential limitations (e.g., irregular tumor shapes).

 

Response 3:  According to your recommendation we changed the sentence’’ ellipsoid volume formula is ideal for tumors having spherical shapes, however it might be less accurate in tumors that are mostly irregular’’in discussion to ‘’The formula we have preferred, as proposed in the literature, facilitates volumetric calculations based on imaging data and provides comparable results. Although this ellipsoid volume formula is ideal for tumors with spherical shapes, it may be less accurate in tumors that are mostly irregular’’ Thank you for your valuable insights.

 

 

Comments 4:

4- The negative TV/LNM association in PTC contrasts with positive correlations in other cancers. This paradoxical finding needs preliminary exploration (e.g., cystic vs. solid morphology). The authors could hypothesize biological reasons (e.g., cystic tumors having lower metastatic potential despite larger volumes) to frame the study’s unique contribution.

Response 4:  We add to Discussion ‘’ Additionally, as it is known that cystic tumors may have lower metastatic potential despite larger volumes, our database was not suitable for distinguishing cystic nodules or cystic formation of PTC.’’

Also we add to concultion ‘’ In our study, although no significant association was found between TD and aggressive tumor characteristics, a significant inverse relationship was observed between LNM and TV in patients with a TD > 2 cm. In other words, small but mighty tumors may exhibit aggressive behavior, even in low-volume PTCs. Further studies with a larger scale, including higher stages, are required to determine whether TV should be integrated into the TNM staging system.’’ Thank you

Comments 5:

5- Only 118/3000 patients were included in this study due to missing 3D measurements in pathology reports. This risks selection bias (e.g., larger/more aggressive tumors may have had dimensions recorded). The authors should compare demographics (age, sex, tumor stage) between included/excluded cohorts to assess this bias.

 

Response 5:  The data of 2064 patients were analyzed for the study, while 3000 patients were mistakenly recorded. Patients with tumors smaller than 0.5 cm and larger than 4 cm were excluded from the study. Statistical analysis was performed on a total of 1607 patients according to the desired criteria. The other group was older but had a lower tumor volume. No significant difference was found between the groups in terms of lymph node metastasis (LNM).

 

	Other group n= 1498	Study sample n= 118
Variable	n (%)	n (%)
Age (years)                  median (Q1-Q3)	47 (37- 56)	43.5 (33 – 52)	0.001
≤55 years	1106 (74.4)	98 (83.1)	0.048
>55 years	380 (25.6)	20 (16.9)
Sex
Female	1213 (81.5)	97 (82.2)	0.939
Male	276 (18.5)	21 (17.8)
Lymph node metastasis
Yes	204 (13.7)	21 (17.8)	0.273
No	1285 (86.3)	97 (82.2)
Tumor diameter (cm) median (Q1-Q3)	1.1 (0.7 - 1.5)	1.5 (1.2 – 2.7)	<0.001
≤ 1 cm	730 (49.0)	19 (16.1)	<0.001
1-≤2 cm	552 (37.1)	56 (47.5)
2-≤4 cm	207 (13.9)	43 (36.4)
n(%): frequency (percentage), SD: Standard deviation, Q1-Q3: 25th – 75th percentiles

Comments 6:

6-  While π/6 (~0.523) is widely used, current literature proposes 0.529 as optimal. The 1.1% discrepancy could affect volume accuracy. Please, justify π/6 with citations or validate using 0.529 in sensitivity analysis.

 

Response 6: In our study, we used π/6 based on the formula proposed in the two referenced articles. However, following your suggestion, calculations were also updated using 0.529, allowing for the evaluation of the sensitivity of the results. All analyses performed for tumor volume (TV) were also conducted using TV2, i.e., π/6 ~0.529. It has been found that similar results were obtained when all analyses were also performed using π/6 ~0.529.

Table 1:  

	π/6 ~0.523	0.529
TV	3.87±5.85 1.18 (0.46 – 4.79)	3.91±5.91 1.19 (0.47 – 4.83)

Figure 2:

π/6 ~0.523
0.529

 

 

Table 2 :

 

Variable	TD (cm)	TV (cm3) 0.529
		All sample (TD≤4 cm)		TD >2 cm
	Median (Q1-Q3)	Median (Q1-Q3)	OR (95% CI)	Median (Q1-Q3)	OR (95% CI)
Extrathyroidal extension
Yes		1.44 (0.57 – 2.78)	0.906 (0.798 – 1.028)	3.21 (2.78 – 8.04)	0.771 (0.585 – 1.017)
No		1.06 (0.44 – 5.84)		8.32 (4.76 – 13.89)
p-value		0.903	0.125	0.026	0.066
Vascular invasion
Yes		2.19 (0.65 – 7.98)	1.027 (0.946 – 1.114)	4.14 (2.78 – 13.33)	0.941 (0.827 – 1.070)
No		0.95 (0.44 – 4.77)		7.85 (4.85 – 12.17)
p-value		0.197	0.527	0.308	0.354
Lymph node metastasis
Yes		1.79 (0.83 – 2.78)	0.921 (0.811 – 1.047)	2.7 8(2.13 – 5.16)	0.617 (0.418 – 0.911)
No		0.86 (0.44 – 5.84)		9.13 (5.05 – 13.89)
p-value		0.432	0.211	<0.001	0.015

 

 

Table 4

Variable	For :0.529
	TV
Dynamic risk stratification
Excellent response	1.19 (0.29 - 5.56)
Biochemical incomplete response	1.04 (0.61 – 4.89)
Structural incomplete response	3.52 (1.15 – 8.27)
Indeterminate response	0.79 (0.28 – 4.00)
p-value	0.633
Five-year disease-free survival
Yes	1.22 (0.44 – 6.02)
No	1.15 (0.58 – 3.15)
p-value	0.850

 

 

Comments 7:

7- Non-routine CLND may under-detect LNM, skewing associations between TV/LNM. The authors should acknowledge this limitation and stratify analysis by dissection extent (e.g., CLND performed vs. not).

 

Response 7: The guidelines on prophylactic central lymph node dissection (CLND) in papillary thyroid cancer (PTC) are conflicting. The American Thyroid Association (ATA) recommends routine dissection only for advanced T3 and T4 tumors, while others, like the European Society of Endocrine Surgeons, consider risk factors such as tumor size, age, and lymph node involvement. The Japanese Association of Endocrine Surgeons supports routine CLND to reduce recurrence and postoperative complications. However, there is opposition, with some arguing that it may increase the risk of damage to parathyroid glands and recurrent laryngeal nerves, with no proven long-term survival benefit. Unilateral dissection is suggested as an alternative to reduce complications, but more research is needed. Our study was conducted at a referral hospital with extensive experience in thyroid disease diagnosis and treatment, which receives approximately 12,000 endocrinology patients monthly. Our patients were evaluated by endocrinology specialists, and ultrasonography ((MCB, DO, RE) using Esaote color Doppler US (Model 796 FDII; MAG Tech nology Co. Ltd., Yung-Ho City, Taipei, Taiwan) and a superficial probe (Model LA523 13-4 5.5e12.5 Mhz). Fine needle aspiration (FNA) biopsy was performed by experienced endocrinologists. Even in cases with low suspicion in the lymph node, FNA and thyroglobulin washout are performed. The patients are then reviewed in multidisciplinary council, including specialists from general surgery, nuclear medicine, and endocrinology, where a decision is made regarding lymph node dissection. Lymph node dissection is performed according to the consensus decision.

 

Comments 8:

8- The authors should report inter-observer concordance for tumor measurements or cite prior validation studies.

 

Response 8: Interobserver concordance of tumor volume refers to the agreement among different observers when measuring a tumor's volume, which is crucial for ensuring reliable clinical decisions and research outcomes. It can be assessed using statistical methods like the Intraclass Correlation Coefficient (ICC) and Bland-Altman analysis. Factors influencing concordance include measurement techniques, observer experience, and tumor characteristics. High concordance enhances standardization in clinical practice and improves prognostic accuracy, while low concordance can lead to variability in treatment decisions.  In response to your suggestion, we will include data on inter-observer concordance within the revised manuscript, highlighting the level of agreement between different observers involved in the measurements. Furthermore, we will reference relevant validation studies that support our measurement techniques and procedures

 

We add ‘’ This statistical significance was not observed in ETE AND VI, we believe it may be due to inter-observer variation in the pathological identification. In a study by Henry K Su they found that inter-pathologist agreement was worst for invasion around thick-walled vascular structures and diagnostic for extrathyroidal extension’’ to discusson thank you.

 

Comments 9:

9- There was no adjustment for confounders (age, sex, BRAF) in logistic regression models. Current literature found age could significantly impact TV-LVI associations. It is highly recommended that the authors perform multivariate analysis adjusting for age, sex, and lymphocytic thyroiditis.

Response 9: After the univariate analyses presented in Table 2, we made multivariate analyses considering the effects of potential confounder variables such as age and gender. The results of these multivariate analyses are presented in Table 3, where both main effects and the interaction effects with TV are included in the model. This allowed for a more accurate evaluation of the relevant relationships. Additionally, it was noted in the discussion section of the study that these relationships could be further evaluated in future studies from the perspective of different variables. Thank you here is the result: When we include lymphocytic thyroiditis in the model, while statistical significance was not observed in TV, statistical significance steel remained for age.

Yas: age

Cinsiyet: sex

Lenfostiktiroidt: lymphocytic thyroiditis

 

Statistical significance was not observed in Vascular invasion.

statistical significance was not observed inLNM.

 

 

 

	Extrathyroidal extension (ETE) OR(95% CI)	Vascular invasion OR(95% CI)	Lymph node metastasis OR(95% CI)
Age (≤55)	0.262 (0.045-1.514)
Sex (male)	0.533 (0.109-2.608)
TV	0.776 (0.589-1.023)
TV*age	1.467 (1.014-2.123)
TV*sex	1.300 (0.955-1.772)
lymphocytic thyroiditis	0.903 (0.286 – 2.852)
lymphocytic thyroiditis	0.901 (0.646 – 1.258)
Overall percentage	80.3
p-value of Hosmer and Lemeshow test	0.357
The p-value from the Hosmer and Lemeshow test was used to assess how well the model fitted the observed data. A higher p-value suggested a good model fit. The Odds Ratio (OR) did not achieve statistical significance, as the confidence interval encompassed the value 1. The significant OR value was emphasized in bold. CI: Confidence interval

 

 

Comments 10:

10- As only 31 patients had tumors >2 cm, limiting the reliability of the TV-LNM association, the authors should acknowledge the low power and validate findings in a larger cohort.

Response 10: we add’’ In addition, the number of patients with TD>2cm in which TV and LNM were related was 43 and represented a small group. The fact that we did not include thyroid cancer types other than PTC and patients with multifocal tumors to create a unique and homogeneous sample may have caused a selection bias. Our study has low power, and we aim to validate the findings in a larger cohort’’ Thank you for your valuable observation

Comments 11:

11- Wide confidence intervals in multivariate analyses suggest instability in estimates.

Response 11: Thank you for your valuable observation. We acknowledge that some of the confidence intervals in the multivariate analysis are wide, which may reflect variability and limited precision in the effect estimates. This is likely due to the relatively small number of events in certain subgroups, despite adjusting for clinically relevant confounders. In response, we have revised the discussion to address this limitation explicitly and caution readers in the interpretation of these estimates. Moreover, we reassessed the model structure and retained only clinically meaningful variables to reduce overfitting.

Comments 12:

12- The authors can consider additional analyses stratified by age groups (e.g. <55 vs ≥55 years).

 

Response 12: Table 1. Demographics and clinical characteristics of all patients and age subgroups (n=118)

	All sample (n=118)	≤55 years (n=98)	>55 years (n=20)
Variable	Mean±SD Median (Q1-Q3) n (%)	Mean±SD Median (Q1-Q3) n (%)	Mean±SD Median (Q1-Q3) n (%)
Age (years)	42.95±12.31 43.5 (33.0 – 52.0)	39.21±9.62 38.0 (32.0 – 46.50)	61.25±6.03 58.5 (57.0 – 63.5)
≤55 years	98 (83.1)
>55 years	20 (16.9)
Sex
Female	97 (82.2)	83 (84.7)	14 (70.0)
Male	21 (17.8)	15 (15.3)	6 (30.0)
Antithyroid antibody positivity (n= 49)
Positive	34 (49.3)	27 (47.4)	7 (58.3)
Negative	35 (50.7)	30 (52.6)	5 (41.7)
Lymphocytic thyroiditis
Yes	47 (39.8)	38 (38.8)	9 (45.0)
No	71 (60.2)	60 (61.2)	11 (55.0)
Tumor diameter (cm)	1.96±0.99 1.50 (1.20 – 2.73)	1.98±0.98 1.55 (1.20 – 2.80)	1.86±1.07 1.40 (1.03 – 2.53)
≤ 1 cm	19 (16.1)	14 (14.3)	5 (25.0)
1-≤2 cm	56 (47.5)	46 (46.9)	10 (50.0)
2-≤4 cm	43 (36.4)	38 (38.8)	5 (25.0)
Tumor volume (cm3)	3.87±5.85 1.18 (0.46 – 4.79)	3.80±5.41 1.23 (0.52 – 5.04)	4.25±7.81 0.68 (0.32 – 2.85)
Extrathyroidal extension (ETE)
Yes	25 (21.2)	21 (21.4)	3 (15.8)
No	93 (78.8)	77 (78.6)	16 (84.2)
Vascular invasion
Yes	21 (17.8)	17 (17.3)	3 (15.8)
No	97 (82.2)	81 (82.7)	16 (84.2)
Lymph node metastasis
Yes	21 (17.8)	17 (17.3)	3 (15.8)
No	97 (82.2)	81 (82.7)	16 (84.2)
TNM
Stage 1	113 (95.8)	97 (99.0)	16 (80.0)
Stage 2	4 (3.4)	1 (1.0)	3 (15.0)
Stage 3	1 (0.8)	0 (0.0)	1 (5.0)
Dynamic risk stratification (DRS) (n=84)
Excellent response	57 (67.9)	48 (66.7)	9 (75.1)
Biochemical incomplete response	6 (7.1)	5 (6.9)	1 (8.3)
Structural incomplete response	4 (4.8)	3 (4.2)	1 (8.3)
Indeterminate response	17 (20.2)	16 (22.2)	1 (8.3)
ATA risk (n=115)
Low risk	71 (61.7)	58 (59.8)	13 (72.2)
Intermediate risk	38 (33.0)	33 (34.0)	5 (27.8)
High risk	6 (5.2)	6 (6.2)	0 (0.0)
n(%): frequency (percentage), SD: Standard deviation, Q1-Q3: 25th – 75th percentiles In comparisons according to age, only a difference was found in terms of TNM distribution (p=0.001).

 

 

Table 5. The comparison of Tumor diameter and tumor volume values based on dynamic risk stratification and 5-year disease-free survival status according to age groups (n=84)

	All sample		TD		TV
Variable	≤55 years (n=72)	>55 years (n=12)	≤55 years	>55 years	≤55 years	>55 years
	n (%)	n (%)	Median (Q1-Q3)	Median (Q1-Q3)	Median (Q1-Q3)	Median (Q1-Q3)
Dynamic risk stratification (DRS)
Excellent response	48 (66.7)	9 (75.1)	1.8 (1.2 – 3.0)	1.30 (0.85 – 2.00)	1.5 (0.4 – 6.5)	0.44 (0.19 – 4.47)
Biochemical incomplete response	5 (6.9)	1 (8.3)	1.8 (1.3 – 2.5)	-	0.7 (0.6 – 5.6)	-
Structural incomplete response	3 (4.2)	1 (8.3)	2.0 (-)	-	1.7 (-)	-
Indeterminate response	16 (22.2)	1 (8.3)	1.6 (1.2 – 2.6)	-	1.1 (0.5 – 4.5)	-
p-value	0.685		0.981		0.923
Five-year disease-free survival
Yes	55 (76.4)	9 (75.0)	1.8 (1.2 – 3.0)	1.3 (0.9 – 2.0)	1.5 (0.5 – 6.5)	0.4 (0.2 – 1.3)
No	17 (23.6)	3 (25.0)	1.7 (1.3 – 2.5)	2.7 (-)	0.9 (0.6 – 2.9)	3.2 (-)
p-value	0.971		0.685	0.600	0.573	0.727
n(%): frequency (percentage), Q1-Q3: 25th – 75th percentiles, TD: Tumor Diameter, TV: Tumor volume

 

Comments 13:

13- Also, the authors can include sensitivity analyses to test the robustness of the findings.

Response 13: For the variables of Extrathyroidal Extension and Lymph Node Metastasis, which showed statistically significant differences in TV values, the effect sizes were found to be 0.80 and 1.15, respectively. The retrospective power analysis results were calculated as 0.50 and 0.85, respectively. Especially in the presence of Lymph Node Metastasis, the sample size for TV comparison results is sufficient, whereas other comparisons should be supported by larger sample sizes.

TD >2 cm  de tV  93-24

Extrathyroidal extension (ETE)  0.37

35 – 7    0.80

Vascular invasion   97 20   0.16

31 11  0.33

 

 

 

Lymph node metastasis  97 20  0.32

 

33 9   1.15

Comments 14-17:

14- Discussion: The inverse relationship between tumor volume and lymph node metastasis in tumors >2cm is not adequately explained. More hypotheses or potential biological mechanisms should be explored.

15- The discussion could benefit from more specific suggestions for future research to address the study's limitations and unexpected findings.

16- While limitations are discussed, they could be more critically analyzed in terms of their impact on the study's conclusions.

17- The small sample size, particularly for tumors >2cm, is a significant limitation that warrants more discussion regarding its impact on the reliability of the findings.

Response 14-17 : Based on your recommendations, we have revisited the discussion and proposed new hypotheses. We have also expanded on our limitations. Thank you very much for your valuable comments and suggestions. We hope that the responses we provided have been sufficient and satisfactory. As you pointed out, we would like to mention that your insights have broadened our perspective for larger-scale studies that include other types of thyroid cancer, higher stages of the disease and incorporate the evaluation of molecular markers

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Thanks to the authors for addressing all the raised concerns.

Best