Purpose To evaluate the incidence and risk factors of lymphedema 10 years after surgical treatment for breast cancer.

Methods Prospective observational hospital-based cohort of women undergoing axillary lymph node dissection. Lymphedema was assessed by indirect volume, measured by circumference, and diagnosed if there was a difference of 200 mL between the arms or if the patient was treated for it. Independent variables were patient, tumour and treatment characteristics. Descriptive statistics were conducted as survival analysis using the Kaplan-Meier estimate. Cox regression was performed, considering a 95% confidence interval (95%CI).

Results The study evaluated 964 women. The cumulative incidence of lymphedema observed was 13.5% at two years of follow-up, 30.2% at five years and 41.1% at 10 years. Final model showed an increased risk for lymphedema among women that underwent radiotherapy (HR = 2.19; 95%CI 1.63–2.94), were obese (HR = 1.52; 95%CI 1.20–1.92), had seroma formation after surgery (HR = 1.46; 95%CI 1.14–1.87), underwent chemotherapy infusion in the affected limb (HR = 1.45; 95%CI 1.12–1.87) or advanced disease staging (HR = 1.41; 95%CI 1.11–1.80).

Conclusions Cumulative incidence of lymphedema was 41.1%. Women undergoing axillary radiotherapy, obese, who developed seroma, underwent chemotherapy infusion in the affected limb and with advanced disease had a higher risk of lymphedema.