Needs, Barriers and Facilitators of Adolescents Participating in a Lifestyle Promotion Program in Oncology: Stakeholders, Adolescents and Parents’ Perspective

Treatments for adolescent cancer can cause debilitating side effects in the short- and long-term such as nausea and malnutrition but also cardiometabolic disturbances. Although the risk for cardiometabolic complications is greater for adolescents with cancer than younger ones, adolescents typically respond poorly to family-oriented health promotion programs. This study aims to assess the needs, barriers and facilitators to healthy lifestyle promotion interventions for adolescents with cancer and how to best adapt these interventions for them. Interviews were held with adolescents treated for cancer (n = 9) and parents (n = 6), focus groups were conducted with stakeholders working in oncology (n = 12) and self-report questionnaires were sent to stakeholders involved in a health promotion intervention (n = 6). At the time of interview, mean age of adolescent participants (40% female) was 17.0 ± 1.9 years (mean age at diagnosis: 14.6 ± 1.6 years). Verbatim and responses to questionnaires were coded and analyzed using qualitative methods. Stakeholder stated that adolescents with cancer need to access activities adapted to their age, to communicate with peers going through a similar experience, and to preserve their schooling and friendships. Barriers to intervention reported by adolescents, parents and stakeholders include lack of motivation, schedule conflicts, fatigue and treatment side effects. Some of the barriers mentioned by adolescents and parents include pain, post-surgery problems, school, physical deconditioning, and lack of time. Facilitators mentioned by adolescents and parents comprise trust in stakeholders’ expertise, personalized approaches, scheduling flexibility. Stakeholders recommended to build trust in the relationship, favoring non-moralizing teachings, adapt interventions to adolescents’ limited attention span and avoiding the use of long-term health benefits as a motivator.


Introduction
In North America, the overall 5-year survival rates for cancer in children (0 to 14 years), adolescents (15 to 19 years), and the adolescent and young adult (AYA) age group (15 to 39 years) range from 83 to 86% [1][2][3][4]. However, survival rates for several cancers vary considerably according to age [3,5]. One striking example is leukemia, with a 5-year

Study Framework and Ethics
This research is part of the VIE (Valorization, Implication, Education) study (web link: https://www.chusj.org/en/soins-services/H/Hematologie/Projet-Vie accessed on 31 August 2022), a non-randomized controlled feasibility study conducted at the CHU Sainte-Justine (CHUSJ) in Montreal (Quebec, Canada). The proposed integrative and personalized program informs newly diagnosed patients and their families about the benefits of adopting early healthy lifestyles, particularly a balanced diet, PA, and stress management to improve quality of life and prevent the incidence of late effects. The design of the interventions has been described in detail [54,57,65]. Briefly, participants 21 years old or younger at diagnosis, treated with chemotherapy or radiotherapy and able to give informed consent (by parents or legal guardians) were invited to participate. Patients were excluded if they were not being treated with chemotherapy and/or radiotherapy. Eligible participants were enrolled between the fourth and twelve weeks after cancer diagnosis. At recruitment, participants underwent an initial evaluation in nutrition, PA and psychological health. Follow-up visits were planned every month by alternating nutrition/PA consults. In parallel, the psychosocial support program was deployed in vulnerable families. Comprehensive nutrition, PA and psychological health evaluations were performed one year after the beginning of the intervention and after the end of cancer treatment. The control group was recruited from patients who had completed their treatment using the same criteria as for the protocol intervention group. No intervention was offered to the control group participants other than standard clinical follow-ups. The current work consists of a qualitative study conducted with a subgroup of the VIE study adolescent participants, in addition to their parents, and stakeholders working in oncology at CHUSJ (health care and research personnel). Participants were recruited from January 2018 until December 2021. Data were collected using focus groups, questionnaires and interviews. This study was approved by the Ethics Review Committee of the CHUSJ (#2021-3129 and #2021-3278).

Stakeholders
Two categories of stakeholders were included in the study: (1) healthcare professionals and hospital-based teachers working with adolescents in oncology at CHUSJ who participated in the focus groups and (2) research health personnel who delivered the VIE study intervention, comprised of research kinesiologists and nutritionists who were eligible to answer the self-report questionnaire. Stakeholders were eligible for participation in focus groups if they were: (1) a healthcare professional or a hospital-based teacher working with children and adolescents in oncology at CHUSJ and (2) exposed to the VIE study (health care personnel). Stakeholders were eligible to answer the self-report questionnaire if they: (1) were a member of the VIE research team, (2) had delivered the nutrition (nutritionists) or PA (kinesiologists) interventions.

Adolescents
Inclusion criteria were: (1) being between 12 and 21 years old at cancer diagnosis; (2) having been treated with chemotherapy and/or radiotherapy; (3) being able to give informed consent (parent or legal guardian); and (4) having participated in the VIE study for a minimum of 1.5 years.

Parents
Inclusion criteria were: (1) being the parent or legal guardian of an adolescent aged between 12 and 21 years at cancer diagnosis who participated in the VIE study for a minimum of 1.5 years and (2) being able to give informed consent.

Recruitment and Data Collection 2.3.1. Focus Groups with Stakeholders
Participants (oncologist, nurse, nutritionist, rehabilitation professional, psychologist and hospital-based teacher) were approached by email. A total of 3 focus groups were held. Discussions were recorded using 2 digital recorder devices. The leader and moderator of the focus groups were two of the authors, J.K. and C.D., respectively. Neither of them delivered interventions to the VIE study participants. Two focus groups lasted 90 min each, of which 30 min of discussions were specific to adolescents with cancer. One focus group lasted 90 min and focused exclusively on adolescents treated in oncology. A total of 150 min of focus group verbatim covering adolescent-related content was transcribed and revised by J.K. and C.D. After the coding and analysis of the third focus group verbatim, data saturation was reached as most themes were recurrent with those from the 2 previous focus groups [66].

Self-Report Questionnaires to VIE Study Stakeholders
The 4-question questionnaire was developed specifically for the VIE study by the research team. The purpose of this questionnaire was to obtain feedback from VIE study stakeholders on their perception of the needs of adolescents treated for cancer and how to optimize their participation in healthy lifestyle interventions. It was sent electronically to stakeholders through a survey transmission platform (Google Forms). Responses to the self-report questionnaires were anonymous.

Interviews with Adolescents and Parents
All adolescents and parents participating in the VIE study were invited to meet the interviewer for a face-to-face interview. Two types of semi-structured interviews were conducted: barriers and facilitators interviews and exit interviews. We established a priori that participants could not take part in both types of interviews. A total of 31 in person interviews (n = 31), conducted individually or as an adolescent-parent dyad, were audio recorded. For the current study, only interviews conducted with adolescents and parents of adolescents were considered (n = 12), including 8 individual interviews about barriers and facilitators and 4 exit interviews. At the time interviews were conducted, all adolescent participants had completed their cancer treatments. Interview duration ranged from 8 to 32 min for a total of 194 min of verbatim. To reduce bias, all interviews were conducted by the same person (C.D.) who is an occupational therapist and doctorate candidate.
To assess the barriers and facilitators to participation in the VIE study, of a total of 8 individual interviews, 5 were conducted with adolescents and 3 with parents. Interviews were held between November 2020 to January 2021. Of the 3 parents interviewed, 2 were parents of teenagers who had themselves participated in a one-on-one interview about barriers and facilitators.
Exit interviews were intended to obtain participants' feedback on the VIE study and suggestions to improve the program or the interventions. These interviews took place during their final assessment at the end of the study and were held between March 2021 and March 2022. A total of 4 exit interviews were conducted with 3 adolescent-parent dyads and with 1 adolescent only.

Data Analysis
Focus groups verbatim and answers to questionnaires were coded and analyzed by J.K. using a thematical analysis with the NVivo qualitative analysis software (version 1.6.1) and using an inductive approach based on the conceptual framework entitled: Consolidated Framework for Implementation Research (CFIR) [67]. The 5 domains of the CFIR construct were used as a guide to assess barriers and facilitators to participation: intervention characteristics, inner setting, outer setting, individual characteristics and implementation process [67]. A little more than 20% of the focus group verbatim was coded and analyzed by a second investigator (C.D.) for inter-judge validation. Coding of the answers to self-report questionnaires were integrated in the same coding tree as the focus groups as questions related to adolescents were identical in both methods. Main themes were identified separately by J.K. and C.D. and were discussed until an agreement was reached. Results were then presented to V.M. to ensure agreement on the main themes.
Interview verbatim was transcribed by C.D. and coded by J.K and C.D. A thematic analysis using deductive and inductive approaches were used to analyze barriers and facilitators' interviews based on the CFIR framework [67]. Because there is no theoretical background or existing knowledge supporting the selection of themes with regard to questions from the exit interviews, an inductive approach was used [66]. For data presentation, all quotations have been translated from French to English as all focus groups and interviews were held in French.

Focus Groups
Participants included occupational therapists, physiotherapists, a nutritionist, a psychologist, a nurse, oncologists and hospital-based teachers working with adolescents in oncology at CHUSJ ( Table 1). The number of participants per focus group varied between 3 and 5, for a total of 12 attending professionals.

Self-Report Questionnaires
Questionnaires were sent to 9 stakeholders who had actively worked with patients, either in the nutrition or the PA components of the VIE study. Completed questionnaires (n = 6) were received from 2 nutritionists and 4 kinesiologists ( Table 1).

Interviews with Adolescents and Parents
A total of 9 adolescents participated in the interviews out of a possible 14 adolescents ( Table 1). The reason for not participating was lack of time. The age at the interview varied between 13.8 and 19.9 years. In total, 6 parents participated in the interviews. Sociodemographic characteristics were collected from 5 parents as 1 did not complete the case report form.

Main Themes Related to Adolescents in Oncology
Qualitative data analysis of the focus groups, self-report questionnaires and interviews resulted in the identification of four main themes: (1) Specific needs of adolescents treated for cancer; (2) Barriers and facilitators to participating in lifestyle promotion interventions; (3) Impact of cancer and treatments on adolescents; and (4) suggestions on how to adapt healthy lifestyle promotion interventions for adolescents in oncology.

Specific Needs of Adolescents Treated for Cancer
Stakeholders agreed on the fact that adolescents should be considered as a distinct group with regard to healthcare services as their motivations and needs are different from those of children and adults. One of the recurrent topics mentioned by stakeholders was adolescents' need for autonomy and freedom, and the need to test limits. One oncologist stated that adolescents need to have a sense of control and to make their own decisions. Stakeholders raised the importance of including adolescents in decision-making, including objective settings, instead of imposing on them the priorities of the study and stakeholders.
Specific to adolescents in oncology, many stakeholders mentioned that adolescents need to have access to services and interventions adapted to their age, to connect with other adolescents experiencing a similar situation, to regain a positive body image and to maintain their physical capacities. Stakeholders, including healthcare professionals, research personnel and hospital-based teachers expressed that adolescents treated for cancer have a need for independence, for their personal space, for time without their parents, to express their feelings and anger, to discover new enjoyable activities adapted to their new reality and medical restrictions. A comprehensive description of the perception of stakeholders regarding the needs of adolescents in oncology expressed during focus or in self-report questionnaires is presented in Table 2, including stakeholders' quotations. Need to keep a certain routine/ Need to maintain limits "I tell my patients, after the announcement of the diagnosis, whether they are younger or older: "well, look, we have the diagnosis, we will start the treatments, there are parts that will be easier than others." But I tell parents: he/she remains your child, you know, you still have to continue to have a routine, well, a routine in quotation marks . . . and [you need to continue to keep] some discipline and a sense of normality as much as possible, not only for your child, but also for the rest of your family. Need to preserve their schooling and friendships "It may sound silly, but let's say a teenager doesn't have to repeat a full school year and that they can come back in the same group of friends. Well, that is extremely important to them." (Oncologist, focus group) Need to regain a positive body image/ Need to maintain physical capacities "[Adolescents treated in oncology need to] Maintain, define, and regain the integrity of their personal image associated with the changes of the body, but also with the decrease in [physical] capacities." (Kinesiologist, self-report questionnaire) "With regards to treatment period, adolescents need to maintain their assets: strength, VO 2 max, flexibility, motor skills, etc." (Kinesiologist, self-report questionnaire)

Needs Stakeholders' Quotations from Focus Groups and Self-Report Questionnaires
Need to confide "They [adolescents in oncology] miss being able to communicate, they miss it a lot." (Psychologist, focus group) "They need to be able to be with and to talk to someone else.

Barriers and Facilitators to Participation in Lifestyle Promotion Interventions
Several perceived barriers and facilitators to adolescents' participation in healthy lifestyle promotion interventions were raised by stakeholders, adolescents and parents (Table 3). They were classified into the five categories of the CFIR framework: intervention characteristics, inner setting, outer setting, individual characteristics and implementation [67]. The most recurrent barriers were related to treatment side effects including fatigue, pain and nausea, lack of time and motivation, schedule conflicts and depression to name but a few. The main facilitators included trust in healthcare providers' expertise, personalized approaches, scheduling flexibility, and respect of the adolescents' limits by the stakeholders. The COVID-19 pandemic was identified both as a barrier and a facilitator. It was found to be beneficial by many parents and adolescents as they did not have to travel to the hospital, but it was also perceived as a barrier by some adolescents who were not interested in participating in remote interventions.

Impact of Cancer on Adolescents
Although this was not a specific study objective nor was it a precise question asked during focus groups or included in the self-report questionnaire, several additional insightful discussion topics raised during focus groups and were cited in the self-report questionnaire. Most of them were related to the multi-level impact of having a cancer diagnosis during adolescence. Stakeholders mentioned the physical consequences of cancer that often lead to a poor body image, but they also referred to the loss of physical capacities which leads to the loss of self-esteem. Stakeholders also reported the psychological and social consequences of having cancer during adolescence. They indicated that adolescents face many changes at the same time and that their world appears to be falling apart. Stakeholders also mentioned that adolescents being treated for cancer often have strained relationships with their parents and perceive a lack of understanding from their friends. Arising results pertaining to consequences of cancer mentioned by stakeholders during focus groups and in self-report questionnaires are highlighted in Table 4. Table 4. Stakeholders' perception of the impact of cancer on adolescents.

Physical Changes Stakeholder Quotations from Focus Groups and Self-Report Questionnaires
Loss of physical capacities "It's not everyone who after that [cancer and treatments] is in great shape. Some have complications that are more important than others. Still, fortunately, we have a population that, after all, in general, is relatively well after their treatment." (Oncologist, focus group) "Motivation to participate [in health promotion interventions] is greatest when a person is confident that they have the ability to perform the required movements. Adolescents [who had cancer] know that they are no longer able to do everything the way they used to." (Kinesiologist, self-report questionnaires) Loss of self-esteem/ Body image issues "It's a period when they live really difficult things and when their body appearance and self-esteem take a big place." (Nurse, focus group) "We were talking about the relationship to the body. How you perceive your body and all this changes a lot. We can just think of our teenagers on steroids during the induction treatment: they swell a lot and they ask themselves "Will I be able to go back to my pre-treatment weight?" We do what we can to reassure them that they probably will. But the concerns are still present and it's scary for them." (Oncologist, focus group)  Grief for activities "I am thinking of this teen who was really grieving not being able to go on her snowboard at the first snow because she had a big pneumopathy. You can present to her any other alternative activity, but she will not do it." (Physiotherapist, focus group) "I find that there is the challenge to mobilize them to move forward. [ . . . ] They [adolescents] can say, among other things. "Ok, I want to go skiing", but they want to go from "I've been lying down for 3 months" to "I'm going skiing tomorrow morning." It's the in-between that must be done in rehabilitation, that they do not want, because they would like to already be there, it is the in between, the path to get there, that is difficult." (Occupational therapist, focus group) Things will never be the same again "I talk to them a lot about [the fact that] it will never be like before. It's hard to hear that. I say the same thing to parents. It's very hard, what I tell them, and I tell them that I know it's hard to hear, but that's the reality. There will never be a "like before", because you are living this experience. But I also tell them that there are going to be beautiful things coming anyway." (Psychologist, focus group)

Suggestions to Adapt Oncology Lifestyle Promotion Interventions for Adolescents
Input from stakeholders, adolescents and parents has generated a rich body of suggestions on how to adapt lifestyle promotion interventions in oncology to adolescents' reality and favor success ( Table 5). The importance for the stakeholder to build trust in his relationship with the adolescent is a central emerging theme. Having a room dedicated to adolescents in oncology has been a central talking point during focus groups and was expressed as a simple means of improving adolescents' quality of life during their hospital stay. The need to implement non-moralizing and individualized interventions was also addressed. Avoid using long-term health as a motivator "You do not realize at 12, 13, 14 years old, that you must take care of your body, in the sense that, for them, it is the present moment [that matters]." (Hospital-based teacher, focus group) "Lifestyle habits are part of a long-term concept, which is probably less of a priority for adolescents in the short term. Since it is less "relevant" to them in the short term, they are less involved." (Nutritionist, self-report questionnaire) "They need to find an external motivation to move. Health is too an abstract concept for it to be a reason for them to be active (even if they are sick)." (Kinesiologist, self-report questionnaire) It's also about aligning our goals and making them evolve together." (Physiotherapist, focus group) "I believe that starting from their objectives can be an important key. In order to discover this objective, it is necessary to develop a relationship of trust. A process that can take time, but it is worth it and requires commitment and consistency in the approach." (Kinesiologist, self-report questionnaire) Celebrate victories "It's also about measuring [objectives] and celebrating victories. [ . . . ] It's to make them realize that they spent 20 min less per day on their tablets. [ . . . ] When you make them realize that they went to sit in their chair 3 times a day and you try to integrate a little bit of physical activity." (Physiotherapist, focus group)

Recommendations Quotations from Stakeholders, Adolescents or Parents
Modernize the approach/Adapt interventions to adolescent's limited attention span "We have to modernize a bit the way we communicate with them. I think that the intervention is important, but the way we get the message across is important too. [..] Maybe it's not a one-hour meeting with a nutritionist, but maybe it's a YouTube clip of I don't know how long, maybe a minute? We know on Tik Tok, it's 15 s. That's the attention that people have. And it's the same for adults." (Oncologist, focus group)

Make interventions attractive
"It would be interesting to optimize the intervention to make it more attractive and more stimulating for adolescents. To involve them more, to develop virtual content, to make teenagers interact together in a group." (Nutritionist, self-report questionnaires).

Develop adolescents' physical literacy/Develop their confidence and motivation
"Physical literacy is defined as "the motivation, confidence, physical competence, knowledge and understanding that a person possesses and that allows them to take charge of their commitment to physical activity for the rest of their life." [ . . . ] "To summarize, I think their [the adolescents] specific needs are to develop their confidence and motivation in a context of lifestyle habits." (Kinesiologist, self-report questionnaires) Ask adolescents their preferences before developing an intervention "The other thing I would say, actually, is to have teenagers either in treatment or who have finished their treatment with us in this discussion. It could really be relevant because, you know, we have ideas, but maybe they're going to be like "No, not at all, you're 'stupid' to think like that." (Oncologist, focus group) Bring adolescents together/ Develop specific activities for them I think we should bring them [adolescents] together and develop specific activities for them that are not moralistic. (Nutritionist, self-report questionnaire) Have a space dedicated for adolescents in oncology "A few years ago, we had thought about this. You know: "how can we make it easier for adolescents to spend their days here?" And that's when the idea of having a room for adolescents emerged." (Psychologist, focus group) "We could ask LEUCAN [a non-profit foundation that supports cancer-stricken children and their families] to organize something for our teenagers . . . They don't need something extraordinary. We won't ask for a loft with non-alcoholic champagne or whatever. But we already have a physical space here, we already have a TV, you do not add the cable, you just make sure to have Netflix, Disney and Prime or whatever. That would make their waiting time here already much easier." (Oncologist, focus group) Address the griefs before initiating activities "I think there are a lot of griefs to deal with before you even start an activity. Finding a way to include friends could be really positive, I think. Show them that they can still do a lot of things despite their illness. Maybe discovering other sports or activities that they can't compare to "before the disease."" (Kinesiologist, self-report questionnaire) Respect adolescents' schedules "I had a lot of sleep problems with the chemotherapy treatments and I would sleep here in the morning at the hospital. And the ladies from the VIE project respected that I was sleeping. They didn't wake me up, contrary to other people in other projects. They understood that if I was sleeping, it was because I needed to sleep." (Male, 16 years old at diagnosis)

Plan interventions between medical appointments
"For sure that it's good between appointments. Sometimes they'd come and get me and we'd play badminton. It helped to pass time between appointments because sometimes it's weird, they give you an appointment at 12:30 pm and the other one is at like 3:45 pm." (Male, 15 years old at diagnosis).

Discussion
This study highlights that, in the context of healthy lifestyle promotion interventions, adolescents battling cancer need to access activities and services adapted to their age, to confide, to express their feelings and anger, to communicate with other adolescents going through cancer and to maintain a sense of normalcy. Barriers to intervention include nausea, fatigue, pain, physical deconditioning, lack of motivation and schedule conflicts. Facilitators comprise stakeholders' flexibility and availability, as well as their capacity to listen and understand adolescents' difficulties. Other facilitators involve interventions being carried out during waiting times between medical appointments and remotely. The COVID-19 pandemic was perceived as both a barrier and a facilitator as remote interventions were alleged to be time-saving for some but demotivating for others. The reported impacts of cancer on adolescents include loss of physical capacities, low selfesteem, body image issues, lack of understanding from friends and loss of autonomy. The main recommendations for adapting health promotion interventions to adolescents in oncology pertain to the importance of building trust in the relationship with the teenager. Other recommendations include favoring non-moralizing teachings, building common objectives with the adolescent, and addressing their griefs before initiating activities.
Similar to our study, the need to connect with other adolescents living a comparable situation in addition to preserving friendships has been reported in children and AYAs during and after cancer treatments [68][69][70][71][72]. This consists of an important unmet need as adolescents and AYAs usually receive care in a pediatric hospital with younger children or in adult care settings [73][74][75][76]. This has been mentioned in a study exploring the needs of AYAs treated for cancer in adult surgery clinics in which they expressed their preference to be treated alongside patients their own age, rather than older adults [74]. In another study exploring the experience of survivors of AYA cancer (16 to 40 years old at diagnosis), it was stated that AYAs struggled to find their place in the health care system [77]. In order to fill these gaps and unmet needs, more multidisciplinary oncology care facilities are being developed specifically for the AYA population [78][79][80][81]. In a review article, key elements to consider when developing a program dedicated to AYAs with cancer included adopting a multidisciplinary approach with health care professionals specialized in AYA cancer and dedicating a space exclusively for AYAs to facilitate interactions and prevent isolation during hospitalization [76].
Maintaining a sense of normalcy is an important need identified in our study, but also in others [44,68,71,73]. We found that adolescents do not want to be perceived by others as being only cancer patients. This was described in two studies that performed semistructured interviews: adolescents with cancer have negative reactions to sympathy and special treatment, they want to be perceived as normal teenagers and be treated as normal as possible [44,68]. A study exploring the preferences of AYAs early after cancer diagnosis revealed that spending time with healthy peers helped them feel more normal during the treatment period [71]. When examining the concept of friendship, it was mentioned that peers often lack the knowledge to treat adolescents with cancer as normal teenagers [73]. In our study, stakeholders mentioned the need for normalcy in multiple contexts: continuing schooling during hospitalization, preserving friendships and maintaining a routine for the adolescent and the rest of the family. Another emergent theme pertained to the importance of allowing adolescents enough time to decide whether they want to participate or not in a healthy lifestyle intervention. To our knowledge, it is the first time this concept has been reported in the context of adolescent oncology. In view of this finding and in consideration for the deployment of future health promotion interventions specific for adolescents, we suggest not to overly limit the recruitment period to allow them time to decide whether or not they want to participate. Offering the possibility to enroll in the intervention at different times during the treatment trajectory could also meet this need.
A study exploring the barriers to the wellness of survivors of pediatric cancer aged between 11 and 30 years and their families found, similar to us, that barriers to PA include fatigue, lack of strength, doctors limiting PA, poor motivation to exercise and depression [32]. Parents feeling torn between supporting their child undergoing cancer treatments and responding to the needs of their other children has also been reported in the literature [82]. In our study, parents did mention lack of time as a barrier to participation, but they also pointed out that the nutrition and PA interventions for their adolescent took weight off their shoulders and allowed them to have more time to take care of their other children.
Autonomy is an important value for adolescents [83]. In our study, stakeholders pinpointed adolescents' desire for autonomy as a barrier to participation in health promotion interventions. This was also mentioned as a barrier to behavioral health interventions targeting healthy adolescents where stakeholders advise teenagers on their personal choices [83]. Conversely, adolescents' need for autonomy has been channeled positively in a doubleblind, randomized, controlled experiment involving more than 500 adolescents to motivate adolescents in adopting healthier food habits [83]. To our knowledge, some of the barriers to participation in PA sessions that have emerged from our study have not been outlined elsewhere in the literature. These include the timing of the beginning of the program, lack of motivation due to the COVID-19 pandemic and pride associated with the loss of physical capacities.
Most studies evaluating the needs of adolescents treated for cancer also included young adults up to 39 years of age [74,[84][85][86] or younger children [64,87]. A qualitative study assessing the problems, stressors and needs of children and adolescents with cancer enrolled 520 participants between 10 and 18 years of age, of which 359 were aged between 13 and 18 years [64]. Participants reported multiple needs including those for emotional support from society, support from nurses and doctors and to access education while hospitalized [64].
Stakeholders participating in our focus groups underscored the impact of cancer on adolescents and the numerous troubles and griefs adolescents battling cancer may experience. In the literature, interviews with adolescents in oncology revealed that cancer was related to pain and treatment side effects, fear of cancer relapse, hospitalization, loneliness, lack of relationships with peers, stigmatization, stress, anxiety, and body image issues [73,88,89].
Our study has highlighted the necessity for building a strong bond to facilitate the communication and collaboration between the teenager and the stakeholders. The importance for healthcare professionals to build trust in the relationship with their patients was outlined in studies evaluating AYAs' priorities and needs during cancer treatments, specifically having close contact and the opportunity of sharing their thoughts with their nurse [74,90].
As mentioned in our study, adolescents with cancer need to access activities and services adapted to their age and need to obtain information and clear answers to their questions, even after the treatment period has ended. Accordingly, in young adult survivors of childhood cancer, the main barriers to health care follow-up were the lack of knowledge related to late effects of primary care physicians [91,92]. Given that it is well documented that survivors of AYA cancer are at higher risk for cardiometabolic complications [26], there is a pressing need for health promotion interventions tailored for this age group to optimize their motivation, engagement and participation. Continuing medical education as well as community teachings should be put in place to ensure that healthcare professionals and adolescent survivors are aware of their health risks.
Based on the study results, we recommend that future health promotion interventions for adolescents with cancer consider assuring the stability of the stakeholders during the intervention in order to promote the establishment of a relationship of trust. Remote interventions should be made available in addition to face-to-face interventions. The option of continuing the intervention after treatment has ended should also be offered. Moreover, initiatives should be put in place to encourage interactions with adolescents experiencing similar situations and with healthy peers in order to break isolation and to maintain a sense of normalcy. In addition, during the development process of a health promotion intervention, we recommend including adolescent patients of different ages, with different diagnoses and at different stages in the treatment trajectory. Finally, because adolescents tend to live in the present moment, the short-term benefits of a healthy lifestyle should be emphasized rather than the long-term health benefits.

Study Strengths and Limitations
A strength of our study is having consulted with stakeholders working in oncology, adolescents treated for cancer and parents which allowed us to gather a comprehensive perspective. Combining three methods of data collection (interviews, focus groups, selfreport questionnaires) contributes to the robustness of the results. By focusing only on adolescents rather than children of all ages or AYAs, our study filled a gap in knowledge in the field of adolescent oncology. Another strength is that half the parents were fathers, a population who is often underrepresented in qualitative studies involving parents of children with cancer [60,93]. Our study has some limitations. It is possible that conducting the study in the hospital where adolescent participants received their treatments and where stakeholders work resulted in a desirability bias. There is a possibility of selection bias since adolescents participating in the VIE study may be more receptive to healthy lifestyle interventions. Indeed, in our study, adolescents who refused to participate in the VIE study or who dropped out of the study were not included. Another limitation is the small sample size for all groups of participants. Lastly, given the monocentric study design, our results may not be generalizable to the general adolescent oncology population.

Conclusions
Developing tailored health promotion interventions for adolescents treated for cancer may optimize their motivation and interest in participating in such programs. Several facilitators to adolescents' participation in health promotion interventions identified in our study were interconnected with the adolescents' needs identified. Health promotion interventions represent a unique opportunity to increase adolescents' knowledge on potential side effects and long-term risks of cancer treatments. Mostly, health promotion interventions could contribute to embedding early healthy lifestyle habits in adolescents treated for cancer. Adolescents' particular needs must be recognized and taken into consideration to provide optimal care and maintain their well-being during the challenging period of cancer treatments and during survivorship.