IntroductionThe primary aim is to determine the factors associated with breast cancer-related lymphedema and to identify new associated factors for the recurrence of breast cancer and depression. The secondary objective is to investigate the incidence of breast cancer-related events (breast cancer-related lymphedema, recurrence of breast cancer, and depression). Finally, we want to explore and validate the complex relationship among multiple factors influencing breast cancer complications and breast cancer recurrence.Patients and methodsA cohort study of females with unilateral breast cancer will be conducted in West China Hospital between February 2023 and February 2026. Breast cancer survivors in the age range of 17–55 will be recruited before breast cancer surgery. We will recruit 1557 preoperative patients with a first invasive breast cancer diagnosis. Consenting breast cancer survivors will complete demographic information, clinicopathological factors, surgery information, baseline information, and a baseline depression questionnaire. Data will be collected at four stages: the perioperative stage, chemotherapy therapy stage, radiation therapy stage, and follow-up stage. Data including the incidence and correlation of breast cancer-related lymphedema, breast cancer recurrence, depression, and medical cost will be collected and computed through the four stages above. For every statistical analysis, the participants will be classified into two groups based on whether they develop secondary lymphedema. Incidence rates of breast cancer recurrence and depression will be calculated separately for groups. Multivariate logistic regression will be used to determine whether secondary lymphedema and other parameters can predict breast cancer recurrence.DiscussionOur prospective cohort study will contribute to establishing an early detection program for breast cancer-related lymphedema and recurrence of breast cancer, which are both associated with poor quality of life and reduced life expectancy. Our study can also provide new insights into the physical, economic, treatment-related and mental burdens of breast cancer survivors.