Clinical outcomes and prognostic factors of pathologic N3 breast cancer treated with modern standard treatments

Background The aim of the present study was to investigate clinical outcomes and identify prognostic factors in pathologic N3 (pN3) breast cancer patients who received the current standard management. Patients and Methods We performed a retrospective study with 333 pN3 breast cancer patients who received curative surgery with postoperative radiation therapy and taxane-based adjuvant chemotherapy from January 2000 to June 2012. The median follow-up period was 58.3 months (range, 7.4-167.9 months). All of the 243 patients who were hormone receptor-positive received endocrine therapy, and trastuzumab therapy was used in 63 of 88 (71.6%) HER2-positive patients. Results Overall, 112 disease recurrences (33.6%) were documented during the follow-up. The first site of recurrence was locoregional in 21 patients (6.3%), distant metastases in 72 patients (21.6%), and both in 19 patients (5.7%). The disease-free survival (DFS) and overall survival were 63.3% and 86.9% at 5 years, respectively. DFS was significantly related to age (> 40 years; P =.008; hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.40-0.87), nuclear grade (I or II; P =.02; HR, 0.64; 95% CI, 0.44-0.93), and positive lymph node ratio (≤ 60%; P =.004; HR, 0.56; 95% CI, 0.38-0.83) in multivariate analysis. HER2-positive patients who were treated with trastuzumab showed more favorable DFS than HER2-negative patients. Conclusion More than 60% of the pN3 breast cancer patients treated with the current standard management lived without disease longer than 5 years. Age, nuclear grade, and lymph node ratio were significant prognostic factors in pN3 breast cancer patients.