Role of postmastectomy radiotherapy in early-stage (T1–2N0–1M0) triple-negative breast cancer: a systematic review

Triple-negative breast cancer (TNBC), which represents 15%–20% of all breast cancers, is defined by the absence of estrogen receptor (ER) and progesterone receptor (PR) and overexpression of human epidermal growth factor receptor 2 (HER2). Owing to the absence of specific therapeutic targets and its aggressive biologic characteristics, TNBC patients often experience a high risk of disease progression and poor overall survival. Furthermore, TNBC exhibits an early pattern of recurrence with a peak recurrence risk at 2–3 years after surgery. Currently, chemotherapy continues to be the mainstay in TNBC patients; however, such treatment leaves them associated with a high rate of local and systemic relapses even in early-stage (T1–2N0–1M0). Therefore, in early-stage disease, greater emphasis is placed on locoregional treatments, based on radiation therapy (RT) after surgery, to reduce local and systemic relapses. However, there are no specific treatment guidelines for early-stage (T1–2N0–1M0) TNBC patients. In this review, we discuss the type of surgery received and the relevant adverse clinicopathologic factors and underlying BRCA1 mutation status regarding the influence of tailing postmastectomy radiotherapy (PMRT). In addition, we assess the role of PMRT in early-stage (T1–2N0–1M0) TNBC patients.