BCL2 IN TRIPLE-NEGATIVE BREAST CANCER TREATED WITH ADJUVANT ANTHRACYCLINE-BASED CHEMOTHERAPY - INDEPENDENT PREDICTOR OF OUTCOME

Background:

Neither targeted therapy, nor predictors for chemotherapy sensitivity are available for triple-negative breast cancer (TNBC). Preclinical data show an association of BCL2 expression and resistance to anthracyclines. The absence of BCL2 expression in prechemotherapy samples is associated with a higher probability of pathological complete response to neoadjuvant doxorubicin-based chemotherapy. The objective of our study was to test whether BCL2 expression could predict outcome in TNBC patients treated with adjuvant chemotherapy.

Patients and methods:

The study included 187 patients with TNBC, 178 of whom were treated with adjuvant chemotherapy (164 had anthracycline-based chemotherapy). BCL2 protein was assessed by immuno-histochemistry.

Results:

High BCL2 expression predicted poor relapse free survival (RFS) in patients treated with adjuvant anthracycline-based regimens (log-rank p = 0.035, hazard ratio, HR 2.37, 95% CI 1.04-5.41) and a trend to poor overall survival (OS) (log-rank p = 0.085). In multivariate analysis of these patients, BCL2, size and nodal status had an independent predictive significance for both RFS and OS.

Conclusion: High BCL2 expression predicted poor outcome in TNBC treated with adjuvant anthracycline-based chemotherapy. BCL2 expression could facilitate decision making on adjuvant treatment in TNBC patients. In patients with high BCL2 expression other types of available adjuvant treatment should be considered. Clinical trials with PARP inhibitors or anti-BCL2 targeted therapy could be another possibility for these patients. The study was presented at ASCO Annual Meeting 2012.

Grants: IGA NS10286, IGA NS10357-3, and Biomedreg CZ.1.05/2.1.00/01.0030.