Predictors of recurrence in postmastectomy patients with one to three positive lymph nodes.

Abstract

1118 Background: Although the role of post mastectomy radiation therapy (PMRT) is well established in women with ≥ 4 positive axillary lymph nodes (ALN), its indications in patients with 1-3 positive ALN is controversial. A recent large meta-analysis suggested a survival benefit in patients with 1-3 positive ALN who received PMRT. However, because recurrence rates in this group are low, identifying a subgroup of patients at higher risk for locoregional recurrence (LRR) could aid decision-making about PMRT. Methods: From an institutional database, 1,333 breast cancer patients who underwent mastectomy between 1996 and 2006 and had 1-3 positive ALN were identified. Among these, T3/T4 tumors and those who received PMRT were excluded. 926 patients were analyzed. The Kaplan-Meier method and Cox regression was used to explore clinicopathologic features that predicted LRR, distant metastases (DM), and recurrence-free survival (RFR). Results: Median follow-up was 7yrs. LRR occurred in 49 patients and DM in 126 patients. LRR and/or DM occurred in 146. On univariate analysis, factors significantly affecting LRR recurrence were increasing tumor size (p=0.04), age <50 (p=0.003), histologic grade (p=0.03), nuclear grade (p=0.008), lymphovascular invasion (LVI) (p<0.0001), and macroscopic ALN metastases (p=0.02). On multivariate analysis, age <50 (p=0.0012) and the presence of LVI (p<0.0001) predicted a higher LRR; increasing tumor size (p=0.0005), age <50 (p=0.04), higher histologic grade (p=0.01), number of positive ALN (p=0.04), LVI (p=0.02), macroscopic ALN metastases (p=0.02), and no chemotherapy (p=0.02) predicted a significantly lower RFR. Conclusions: Pts with T1-2 tumors and 1-3 positive ALN are at low risk of isolated LRR; however, patients <50 and with LVI may have additional risk that warrants consideration of PMRT.