The INSIGHT study, whose name spells out its mission as Identify Nonresponse and Strategies to Improve Questionnaires’ Trustworthiness, adopted a mixed-methods design that treated nonresponse not as a statistical nuisance but as a phenomenon with identifiable, and potentially correctable, causes. The first phase was a needs assessment with two complementary strands. On the quantitative side, the team carried out a statistical analysis of the FASTRACS trial data to pinpoint the subgroups of participants at higher risk of falling silent, comparing the characteristics of respondents and nonrespondents at successive follow-up points. On the qualitative side, they conducted individual interviews with survivors to hear, in their own words, the barriers that had pushed them away from questionnaires and the facilitators that might draw them back.

What emerged from that analysis was strikingly consistent with what survey methodologists have long suspected but rarely tested inside an ongoing oncology trial. Nonrespondents were younger than their responding counterparts, and they reported more systemic side effects from their breast cancer treatment, the fatigue, pain and cognitive fog that follow chemotherapy and endocrine therapy. Three broad domains of influence were identified: the breast cancer experience itself, the design of the questionnaires, and the context in which completion took place, whether at the hospital or at home. A younger woman juggling a return to work, childcare and lingering treatment toxicity, the findings suggest, experiences a mailed or online questionnaire very differently from an older, retired participant with fewer competing demands.

Armed with that diagnosis, the researchers turned to a participatory development process. A brainstorming session brought together breast cancer survivors drawn from the FASTRACS Intersectoral Strategic Participatory Committee, a standing body created to embed patient and stakeholder voices in the project, and additional phone interviews gathered participant perspectives. This was not a token consultation exercise. The ideas that survived into the final intervention were those the survivors themselves judged acceptable, practical and likely to matter to their peers. The researchers then telephoned trial participants to introduce the strategies and to gauge their willingness to complete questionnaires under the new conditions, effectively testing acceptability in real time before formal evaluation.

Four concrete components made it into the FASTRACS-INSIGHT intervention, and their simplicity is part of their charm. Participants received personalized reminder cards, each accompanied by a tea bag, a small gesture of warmth designed to make the request feel human rather than bureaucratic. Printed paper questionnaires were sent to every participant, removing the digital barrier for those who preferred or needed pen and paper. A medical appointments booklet, bundled with a FASTRACS-branded pen, offered a practical tool that kept the study visible in daily life. Finally, the team reinforced telephone-based questionnaire completion, allowing women to answer surveys with a researcher over the phone, and deployed text message reminders timed to prompt action without overwhelming it.

The evaluation phase compared response rates before and after the intervention was rolled out, and the results were unambiguous. At the third follow-up time point, designated T3, questionnaire response rates rose from 54.4 percent to 74.4 percent, a difference that was statistically significant at p less than 0.001. At the fourth time point, T4, the improvement was even more dramatic: completion climbed from 46.2 percent to 76.7 percent, again with p less than 0.001. In plain terms, roughly half of the survivors who had been dropping out of the study’s data collection were brought back into the fold. For a longitudinal randomized controlled trial, in which every lost questionnaire erodes statistical power and invites attrition bias, a gain of twenty to thirty percentage points at successive waves is not a cosmetic improvement but a meaningful rescue of the study’s evidentiary foundation.

The findings also speak to a deeper methodological problem in health research. Survey nonresponse is rarely random, and the INSIGHT study confirms that in the context of cancer survivorship it is patterned by age and by treatment burden. Younger survivors face what the literature describes as distinct work-related, clinical and psychological pressures during the return-to-work period, and women experiencing more systemic side effects may find a lengthy questionnaire an intolerable additional demand rather than a welcome chance to contribute. If researchers ignore these patterns, their longitudinal datasets become progressively skewed toward older, healthier, more engaged participants, quietly distorting the very outcomes, quality of life, fatigue, functioning and employment, that survivorship research aims to measure. By identifying who was at risk and why, INSIGHT offered a template for protecting data quality prospectively rather than statistically patching it after the fact.

Equally instructive is the participatory character of the solution. None of the four components, the reminder cards with tea bags, the universal printed questionnaires, the appointments booklet with pen, or reinforced phone completion and text reminders, involved sophisticated technology or prohibitive cost. What distinguished them was that they were co-designed with the people expected to use them. The authors argue that involving breast cancer survivors in developing the intervention was essential to tailoring it to their needs, and the trial’s before-and-after results give empirical weight to that claim. The approach echoes the intervention mapping framework the FASTRACS team has used throughout the parent trial, in which theory, evidence and stakeholder input are systematically combined to design health behavior interventions. Response behavior, INSIGHT demonstrates, is itself a behavior that can be mapped, understood and changed.

The implications extend well beyond this single French trial. Randomized controlled trials in oncology routinely lose participants to questionnaire fatigue, and systematic reviews of survey methodology have catalogued dozens of strategies, from monetary incentives to shortened instruments, with mixed and context-dependent results. What INSIGHT adds is a replicable, multi-step playbook: analyze who is not responding, interview a sample to understand their reasons, co-develop low-burden interventions with a patient committee, and evaluate the package with straightforward before-and-after comparisons. The registered protocols underlying the work, the FASTRACS-RCT under NCT04846972 and the RECOVA-FASTRACS qualitative protocol under NCT05919498, with an amendment covering INSIGHT, give the effort a transparency that methodologists will welcome. Informed consent was obtained from all participants, and the authors report no competing interests, with funding from the League against cancer in the Auvergne Rhône-Alpes region, the National Agency for the Improvement of Working Conditions, the National Cancer Institute, and joint support from the Pension and Welfare Fund for Notaries’ Clerks and Employees.

There is a quietly radical message here for the research enterprise. Behind every unreturned questionnaire is a person navigating one of the hardest chapters of her life, and the difference between a study that retains its participants and one that loses them may come down to whether the researchers asked those participants what would help. A tea bag and a handwritten-feeling reminder card will not cure cancer or eliminate treatment side effects, but they signal respect, and respect, as the FASTRACS-INSIGHT team has shown with response rates rising from the mid-forties to the mid-seventies, turns out to be a remarkably effective instrument of science. For the growing community of survivorship researchers studying return to work after cancer, an outcome with well-documented personal and economic stakes, the lesson is clear: sustainable data collection is not a logistics problem to be solved in a back office, but a relationship to be built with the survivors themselves, one thoughtfully designed touchpoint at a time.

Subject of Research: Nonresponse causes and response-rate improvement strategies in a randomized controlled trial of return-to-work support for breast cancer survivors

Article Title: Understanding nonresponse and strategies to improve response rates in a randomized controlled trial among breast cancer survivors: the FASTRACS-INSIGHT mixed-methods study

Article References: Soulier, A., Blazer, A., Préau, M., Guittard, L., Maurin, A., Fervers, B., Letrilliart, L., Carretier, J., Broc, G., Fassier, J.-B., Péron, J., Rouat, S., & Lamort-Bouché, M. (2026). Understanding nonresponse and strategies to improve response rates in a randomized controlled trial among breast cancer survivors: the FASTRACS-INSIGHT mixed-methods study. Journal of Cancer Survivorship. https://doi.org/10.1007/s11764-026-02132-z

Image Credits: AI Generated

DOI: 10.1007/s11764-026-02132-z

Keywords: breast cancer, cancer survivors, randomized controlled trial, survey nonresponse, questionnaires, response rates, return to work, cancer survivorship, mixed-methods study, participatory research, reminder strategies, data quality