Résumé
Background: Mindfulness-Based Interventions (MBIs) are recognized as beneficial in oncology supportive care. While qualitative analyses of mindfulness program experiences exist, this is the first mixed methods study to examine patients' experiences after participating in the online Mindfulness-Based Cancer Recovery (e-MBCR) program. Methods: The SERENITY study was a pilot randomized controlled trial evaluating the early implementation, and effects of the e-MBCR program for women with breast or gynecological cancer in a French-speaking context. This article reports on secondary outcomes from a mixed methods analysis, exploring psychosocial aspects through questionnaires and participants' experiences through interviews. Sixty-two patients were randomized in a 2:1 ratio. Quantitative assessments were carried out at three timepoints; qualitative interviews only post-intervention. Both datasets were analyzed separately, then merged for interpretation. Results: The intervention group showed a significant reduction in depression compared to the control group, with a medium effect size post-intervention. While other psychological measures did not show significant differences, this exploratory analysis revealed favorable trends, particularly in anxiety, spiritual well-being, and post-traumatic growth. At 3-month follow-up, most scales showed a diminished effect compared to post-intervention. Qualitative interviews revealed four themes: a safe and validating environment, acquiring skills and taking action, enhanced well-being, and exposure to memories of cancer. This last dimension was a source of beneficial inner work for most participants, although it was a deeply challenging experience for four women. Conclusion: Participation in the e-MBCR program led to beneficial experiences, notably self-exploration, and enhanced self-efficacy. However, MBIs can also bring up challenging experiences, which are important to acknowledge.