Citizen participation in cancer research is growing intensively. In this context, the IMPAQT research project aims to promote the participation of (former) cancer patients in all stages of research. It was in response to the needs of the patient-researchers of the IMPAQT research group that the Perce-Neige project was developed. Based on the principles of community participation and collaboration, this project has a dual objective: methodological, aimed at understanding collaboration and characterizing the community approach, and empirical, which concerns caregivers’ perceptions of cognitive disorders related to cancer treatments. All the methodological tools aimed at meeting these objectives were co-constructed by the entire IMPAQT group. The research participation of the people concerned enables a novel way of linking expert and experiential knowledge and necessitates specific modes of organization. Also, the co-construction of research and methodological tools requires a regular updating of knowledge, as well as a capacity for reflection and an openness to reconsidering the approach. It also appears that the mobilization of the people concerned, who possess experiential knowledge, raises emotional issues. In conclusion, the participation of the people concerned in research constitutes an essential lever in the identification, elaboration, and social and psychosocial contextualization of health issues in cancerology.