Are There High-Risk Prognostic Factors for Isolated Locoregional Recurrence in Patients With Early-Stage Breast...

This study aims to investigate whether there are subgroups of patients with early-stage breast cancer (BC) treated with radical mastectomy that are at high risk of locoregional recurrence (LRR) and could benefit from postmastectomy radiation therapy (PMRT).

We retrospectively reviewed patients with early-stage BC treated with mastectomy at our institution between December 2009 and December 2018. Tumors were classified according to molecular subtype and known prognostic factors. Outcomes were estimated using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test, while Cox proportional hazards regression was applied to estimate hazard ratios for evaluating associations between prognostic factors and survival. A P value of <.05 was considered statistically significant.

A total of 670 patients who met the selection criteria were identified. Median age was 59.4 years (IQR, 48-72), and the median follow-up was 107.1 months (IQR, 80.3-138.6). Among the cohort, 257 patients (38.3%) had T2 tumors, 249 (37.1%) were pN1, 186 (27.8%) had grade 3 tumors, 134 (20%) presented with lymphovascular invasion (LVI), 116 (17.3%) were HER2-positive, and 55 (8.2%) had triple-negative disease. LRR rates at 2, 5, and 8 years were 1.4%, 2.9%, and 3.5%, respectively. On univariate analysis, the presence of LVI, G3, tumor size (T), nodal involvement (pN1), estrogen receptor-negative status, triple-negative phenotype, and Ki-67 expression were significantly associated with an increased risk of LRR. Notably, LVI-positive patients had significantly higher locoregional and regional recurrence rates at 8 years (9.5% and 9.4%, respectively) compared to LVI-negative patients (1% and 1.1%). Multivariate analysis confirmed LVI as a strong and independent predictor of recurrence across all models.

This study confirms the prognostic relevance of several pathologic factors in predicting LRR, with particular emphasis on the independent role of LVI, in patients with early-stage BC treated with mastectomy and not receiving PMRT. In patients with early-stage BC with T1-T2 tumors and 1-3 positive axillary lymph nodes with the presence of LVI, PMRT should be considered.