513PD - BRCA status, molecular profile and clinical variables in primary bilateral breast cancers: a population-based cancer registry study

Date 01 October 2012
Event ESMO Congress 2012
Session Public health and familial cancer
Topics Breast Cancer
Familial Cancer
Presenter Antonino Musolino
Authors A. Musolino1, M.A. Bella1, M. Michiara2, P. Zanelli3, N. Naldi1, B. Bortesi1, P. Sgargi2, R. Camisa1, T.M. Neri3, A. Ardizzoni4
  • 1Medical Oncology Unit, University Hospital of Parma, 43126 - Parma/IT
  • 2Medical Oncology Unit, University Hospital of Parma and Cancer Registry of Parma Province, Parma/IT
  • 3Medical Genetics Unit, University Hospital of Parma, Parma/IT
  • 4University Hospital of Parma, 43126 - Parma/IT

Abstract

Introduction

Incidence of primary bilateral breast cancer (BBC) is rare and does not exceed 5%. BRCA1/2 mutation carriers diagnosed with breast cancer have a strong life time risk of developing contralateral breast cancer. Objectives To address both the proportion of BBC associated with BRCA1/2 germline mutations and the contribution of germline mutations to the clinical features and outcome of these tumors.

Materials and methods

We identified 263 BBC patients (pts) from a cohort of 9585 women with a first primary breast cancer systematically collected by the Cancer Registry of Parma Province from 1978 to 2006. Among these, 55 women, unselected for family history, were subjected to BRCA1/2 testing. In addition, 55 unilateral breast cancer pts, which tested negative for BRCA1/2 mutations, were evaluated as control group.

Results

BRCA mutations were detected in 13 (24%) of 55 BBC pts. Family history of breast cancer was identified in 8% of these pts compared with 7% of non-carriers (P = 0.64). Synchronous BBC was significantly rarer in BRCA carriers than in non-carriers. In addition, BRCA-positive pts were younger at diagnosis than BRCA-negative ones. The combination of high histologic grade, ER, PR, and HER2 negativity in both bilateral tumors was more frequent among BRCA-1 positive tumors than BRCA-2 positive and non-BRCA tumors (P < 0.001). Taken collectively, BRCA-positive BBC correlated with triple negative status compared to non-BRCA BBC and unilateral breast cancer controls (P < 0.001). There were no survival differences between BRCA-positive and non-BRCA tumors.

Conclusions

Our data show that the combination of BBC occurrence and breast tumor phenotype can provide an efficient model for identifying individuals with high risk for BRCA mutations and support the hypothesis that BBC in BRCA carriers is qualitatively distinct from non-BRCA BBC and from sporadic, unilateral breast cancer. Further studies of incident cases are needed to better define the prognostic value of BRCA mutations.

Disclosure

All authors have declared no conflicts of interest.