Predictors of locoregional outcome in patients receiving neoadjuvant therapy and postmastectomy radiation

Background: The objective of this study was to identify predictors of locoregional recurrence (LRR) after neoadjuvant therapy (NAT) and postmastectomy radiation (PMRT) in a cohort of patients with stage II through III breast cancer and to determine whether omission of the supraclavicular field had an impact on the risk of LRR. Methods: The authors reviewed records from 464 patients who received NAT and PMRT from January 1999 to December 2009. Results: The median patient age was 50 years (range, 25-81 years). Clinical disease stage was stage II in 29% of patients, stage III in 71%, and inflammatory in 14%. Receptor status was estrogen receptor (ER)-positive in 54% of patients, progesterone receptor (PR)-positive in 39%, human epidermal growth factor receptor 2 (HER2)-positive in 24%, and negative for all 3 receptors (triple negative) in 32%. All patients received NAT and underwent mastectomy, and 19.6% had a complete pathologic response in the breast and axilla, 17.5% received radiation to the chest wall only, and 82.5% received radiation to the chest wall and the supraclavicular field; omission of the supraclavicular field was more common in patients with lower clinical and pathologic lymph node status. The median follow-up was 50.5 months, and the 5-year cumulative incidence of LRR was 6% (95% confidence interval, 3.9%-8.6%). Predictors of LRR were clinical stage III (P =.038), higher clinical lymph node status (P =.025), higher pathologic lymph node status (P =.003), the combination of clinically and pathologically positive lymph nodes (P <.001), inflammatory presentation (P =.037), negative ER status (P =.006), negative PR status (P =.015), triple-negative status (P <.001), and pathologic tumor size >2 cm (P =.045). On univariate analysis, omission of the supraclavicular field was not associated significantly with LRR (hazard ratio, 0.89; P =.833); however, on multivariate analyses, omission of the supraclavicular field was associated significantly with LRR (hazard ratio, 3.39; P =.024). Conclusions: Presenting stage, receptor status, pathologic response to neoadjuvant therapy, and omission the supraclavicular field were identified as risk factors for LRR after neoadjuvant therapy and PMRT.