Rethinking on the management strategy of malignant phyllodes tumor of the breast: An analysis based on the SEER database

Malignant phyllodes tumor of the breast (MPTB) is a rare breast neoplasm that has a high recurrence rate and its optimal treatment strategies remain controversial. Our study used the most up-to-date database to determine prognostic factors that predict cancer-specific survival (CSS) and to evaluate the effects of different treatment strategies for MPTB. We performed a retrospective cohort study using the National Cancer Institute’s Surveillance, Epidemiology, and End Results database. Women who were diagnosed with MPTB from 2000 to 2019 were included. Kaplan–Meier method and Cox proportional hazards regressions were used to evaluate the prognostic power of variables on CSS. A total of 1902 women with MPTB were included in the study, with a median follow-up duration of 87.5 months. Age was found not to independently predict CSS in patients with tumors larger than 10 cm (P = .235). Mastectomy was performed on a total of 898 (47.2%) patients including 210 women (23.4%) undergoing radiotherapy after surgery. Mastectomy showed worse CSS when compared with breast-conserving surgery in patients with tumors smaller than 10 cm. Patients undergoing radiotherapy were not inferior to non-radiotherapy patients on CSS when patients were stratified by tumor size. Breast-conserving surgery showed survival benefits for patients with small tumors (T1 and T2). Patients with radiotherapy were not inferior to non-radiotherapy patients on CSS. Treatment of patients with MPTB should be carefully selected based on different tumor sizes.