Outcome for triple negative breast cancer in a retrospective cohort with an emphasis on response to platinum-based neoadjuvant therapy.

PURPOSE: The rate of pathological complete response (pCR) for patients with triple negative breast cancer (TNBC) is increased when carboplatin is added to neo-adjuvant chemotherapy (NACT). However, while phase III trial data showing a survival benefit are awaited, carboplatin is not yet standard-of-care for TNBC. The aim of this study was to examine the rate of pCR and the outcome for those treated with carboplatin and to examine the predictors of response to therapy.

METHODS: The retrospective series comprised 333 consecutive patients with TNBC (median follow-up time, 43 months). Adjuvant chemotherapy was given to 51% (n = 168) of patients and 29% (n = 97) received anthracycline-taxane NACT with carboplatin given to 9% (n = 31) of patients.

RESULTS: Overall, 25% (n = 78) of patients experienced a breast cancer recurrence and 22% (n = 68) died from disease. A pCR breast and pCR breast/axilla was more common in those who received carboplatin (n = 18, 58% and n = 17, 55%, respectively) compared those who did not (n = 23, 36% and n = 18, 28%, respectively) (p = 0.041 and p = 0.011, respectively). By multivariable analysis, carboplatin and high tumor grade were independent predictors of pCR breast/axilla (ORnon-pCR  = 0.17; 95% CI 0.06-0.54; p = 0.002; and ORnon-pCR  = 0.05, 95% CI 0.01-0.27; p < 0.001, respectively). pCR breast/axilla was an independent predictor of DFS (HRnon-pCR =6.23; 95% CI 1.36-28.50; p = 0.018), metastasis-free survival (HRnon-pCR  = 5.08; 95% CI 1.09-23.65; p = 0.038) and BCSS (HRnon-pCR  = 8.52; 95% CI 1.09-66.64; p = 0.041).

CONCLUSION: Carboplatin therapy and high tumor grade are associated with a significant increase in the rate of pCR, which is an independent predictor of outcome. These data support the use of carboplatin in NACT for TNBC, while results from phase III studies are awaited.