Predictors of tumor progression during neoadjuvant chemotherapy in breast cancer.

PURPOSE Although most breast cancer patients who receive neoadjuvant chemotherapy (NCT) have a tumor response, a small proportion experience progressive disease (PD). Predictors of response have been reported, but predictors for progression have not been identified. We sought to identify predictors of tumor progression during NCT with the ultimate aim of identifying patients who might benefit from a first-line surgical approach or from novel targeted therapies. PATIENTS AND METHODS Data were obtained from reviewing medical records of patients with stage I to III breast cancer who received NCT (anthracycline and/or taxane based). Statistical analysis was performed to compare patients with any response or stable disease with patients with PD. RESULTS One thousand nine hundred twenty-eight patients received NCT; 1,762 patients (91%) had some response, 107 (6%) had stable disease, and 59 (3%) had PD at some point during NCT. Factors predictive of PD included African American race (P = .002), tumor (T) status (P = .002), and American Joint Committee on Cancer clinical stage (P = .02). Histopathologic features of PD were high tumor grade (P = .005), high Ki-67 score (P = .002), and negative estrogen receptor (ER)/progesterone receptor (PR) status (P < .001/P < .001). Pre-NCT T status, race, and ER status were independent predictors of progression in multivariate analysis. Disease progression was a negative predictor of distant disease-free survival and overall survival in multivariate analysis (P < .001). CONCLUSION Factors predictive of PD include race, advanced tumor stage, high nuclear grade, high Ki-67 score, and ER/PR negativity. Because many of these variables are also associated with response to NCT, novel molecular predictors are needed to identify patients at risk for progression on standard NCT.