Locoregional recurrence risk factors and the impact of postmastectomy radiotherapy on patients with tumors 5 cm or larger

Background Locoregional recurrence (LRR) after mastectomy reduces the patient’s quality of life and survival. There is a consensus that postmastectomy radiotherapy (PMRT) helps achieve locoregional control and reduces LRR. However, in patients with large tumors, the question of which variables affect the likelihood of LRR and the role of PMRT have been subjects of substantial controversy. This study investigated what the risk factors are for LRR and the efficacy of PMRT in this patient population. Methods This retrospective study examined 589 cases of invasive breast carcinoma with tumors 5 cm or larger from 1998 to 2008. We divided the study population into 3 groups: patients with negative nodes, 1–3 positive nodes, and ≥4 positive nodes. The relationship between various clinicopathological variables and LRR was examined, and the relationship between LRR and PMRT was estimated. Results During the median follow-up of 44.2 months, 38 (6.5 %) patients experienced LRR. In the multivariate analysis, independent risk factors for LRR included pectoral invasion in patients with 1–3 positive nodes, severity of lymphatic invasion, estrogen receptor-negative status, and a nodal ratio of positive/excised nodes >0.50 in patients with ≥4 positive nodes. In patients without positive nodes, none of the examined variables were significantly associated with LRR. Although patients treated with PMRT had good outcomes, there was no significant difference. Conclusions With systemic therapy and adequate lymph node dissection, PMRT by itself was of limited value in establishing locoregional control. Due to the very low incidence of LRR observed, PMRT was not necessary for patients with large tumors without lymph node metastasis. Further examination and consensus about the indications for PMRT in patients with 1–3 metastatic nodes are needed.