Cross-sectional nationwide mixed-methods population-based study of living conditions, and identification of sexual and fertility profiles among young women after breast cancer in France: the Candy study protocol.

Introduction: At the end of the treatment, many young breast cancer (BC) survivors face difficulties related to fertility and sexuality, mainly due to the side effects of treatment. Integrating patient needs into medical decisions is becoming increasingly essential for high quality care. To this end, there is a compelling need to elicit patients' perspectives through qualitative studies, to understand their experiences and needs in the aftermath of cancer. We aim to: (1) identify clinical, social and economic determinants of sexuality and fertility, and describe other living conditions of young BC survivors in France; and (2) explore young women's experience after BC in relation to clinical and information needs about fertility preservation and sexual health.

Methods And Analysis: This is a mixed-methods, cross-sectional, population-based study. In the quantitative component, women diagnosed with non-metastatic BC between 2009 and 2016 and aged 40 years or younger at diagnosis will be identified through the French network of cancer registries (FRANCIM). Participants will complete self-report questionnaires including standardised measures of sexuality, health-related quality of life (HRQoL), anxiety, depression, social deprivation and social support. Fertility and professional reintegration issues will also be assessed. Sexuality profiles will be identified by ascending hierarchical classification and fertility profiles will be identified by latent class models. Determinants of sexuality, fertility and HRQoL will be identified using a mixed regression model. Subsequently, semistructured interviews will be performed with a sample of 30 women who participated in the quantitative study. Interviews will be recorded, transcribed synthetically and content analysis will be performed, with the aid of NVivo software.

Ethics And Dissemination: This study will be performed in accordance with the declaration of Helsinki. The protocol was approved in October 2020 by the Committee for the Protection of Persons North-West III (20.07.16.44445) and by the French national data protection authority (CNIL-MR003 No1989764-v0).The results of this project will be communicated to the scientific community through publications in international scientific peer-reviewed journals and communications to national and international congresses. Popularised results will also be provided to patient associations. The results of Candy project will also be published on the website of the sponsor, www.cgfl.fr.