Pathologic complete response (pCR) to predict patients’ survival in luminal breast cancer.

Abstract

e11615 Background: Gene expression studies have demonstrated that breast cancer can be divided into three major subgroups : Luminal, Human Epidermal Growth Factor Receptor-2 (HER2) over-expression and Oestrogen negative (ER-). Luminal breast cancer is well known for its better prognosis compared with the other types. Conversely, response is less effective by pCR criteria after chemotherapy. This work aimed to evaluate if pCR could still be considered as a surrogate marker in luminal subgroup according to immunohistochemical classification : Hormonal receptor positive and HER2 negative (HR+HER2-). Methods: All 132 luminal early breast cancer patients treated by neo-adjuvant chemotherapy (NAC), in our institution from 2001 to 2007 were included in this study. NAC treatment comprised anthracycline alone, taxotere alone or sequential use of these two drugs. Survival curves have been established according to the Kaplan-Meier’s method. Comparison of curves were performed in using Log-rank test. The median of follow-up was 102 months (range 59 – 142 months) in October 2012. Results: Median age was 53.5 (range 34–78) years and median initial tumor size was 4cm (range 1-10). Objective response rate was 65% (86 patients), of which 8% (10 patients) had a complete response after 6 courses. One hundred and six (80%) underwent breast conservation surgery. Seven patients (5%) and ten patients achieved pCR (8%) according to Chevallier and Satatloff’s classification, respectively. Twenty patients did relapse and 18 patients died. At 10 years, Disease-free survival (DFS) and overall survival (OS) rate was 81% and 84%, respectively. All pCR patients, regardless of classification, did not relapse. However, the patients who achieved a pCR had not a significant difference in DFS and OS compared to the patients who did not. Conclusions: pCR was not a surrogate marker after a relatively short survey of 100 months for luminal breast cancers, who have generally late relapses. However, sixty five percent of patients had >50% reduction in primary tumor and 80% of patients had a breast conservation. Further studies are needed to identify new markers able to predict patients’ survival.