Bradley-Garcia, MeenakshieTanguay, Annick F. N.Sekeres, Melanie J.2026-03-172026-03-172026-02-06BMC Women's Health. 2026 Feb 06;26(1):154https://doi.org/10.1186/s12905-026-04325-1http://hdl.handle.net/10393/51451Abstract Background Breast cancer is the most diagnosed cancer worldwide, affecting one in four women diagnosed with cancer. Cancer treatments, particularly chemotherapy, can adversely impact mental health, contributing to increased stress, anxiety, depression, fatigue, and poor sleep quality. This study investigated the long-term psychological effects of cancer treatment among breast cancer survivors and explored interactions between these factors. Methods We recruited Canadian women aged 30 to 65 with a history of breast cancer who were at least 6-months post-treatment (n = 49) and age-matched control participants (n = 44). Participants provided demographic and health information and completed online questionnaires assessing stress, depression, trait and state anxiety, fatigue, sleep quality, and physical activity. Results Breast cancer survivors reported significantly higher levels of stress (p = .004), depression (p < .001), state anxiety (p = .003), trait anxiety (p = .02), fatigue (p < .001), as well as poorer sleep quality (p < .001) compared to non-cancer controls. Physical activity levels and leisure-time exercise did not differ between groups (p = .13 and p = .17, respectively). While physical activity was not significantly correlated with mental health factors in either group (p’s > 0.05), most mental health factors were correlated with each other in both groups (p’s < 0.05). Conclusion Our findings enhance understanding of the long-term mental health effects of cancer treatment in breast cancer survivors, providing strong evidence that breast cancer survivors continue to experience significant psychological challenges – including stress, anxiety, depression, fatigue, and sleep disturbances. Given these persistent challenges, it is critical to incorporate comprehensive mental health assessments into cancer survivorship plans to identify psychological concerns and inform treatment strategies that address the interconnectedness of these issues.Journal Article2026-03-17enThe Author(s)