Breast cancer survivors with BRCA mutations at risk for second cancer

San Antonio Breast Cancer Symposium

SAN ANTONIO — Carriers of a BRCA mutation who had had previous breast cancer were about three times more likely to develop a second cancer in the contralateral breast, according to findings presented here.

Alexandra J van den Broek, MSc, of the Psychosocial Research and Epidemiology department at the Netherlands Cancer Institute in Amsterdam, said that women who survive a first breast cancer are at a greater risk to develop a contralateral breast cancer than women in the general population for developing a first primary breast tumor. Women who carry a germline mutation in either the BRCA1 or the BRCA2 are at a particularly increased risk for a synchronous or metachronous bilateral breast cancer.

"We wanted to provide precise risk estimates and get better insight into factors that predict the risk for contralateral breast cancer in this group of high risk women," van den Broek said.

There were 5,061 women surveyed in the most recent analysis. Eligible women had been diagnosed with unilateral, invasive breast cancer at 10 hospitals in the Netherlands between 1970 and 2003.The carriage rate of BRCA1 or BRCA2 mutation was 4.2% (n=211).

The overall rate of development of contralateral breast cancer was 8.6% at a median of 8.4 years of follow-up.

The overall 10-year risk for developing contralateral breast cancer was 6.0% for non-carriers of the mutation and 17.9% for carriers.

Carriers who were diagnosed at age 40 years or younger than 40 years had a 10-year risk for contralateral breast cancer of 26.0%. The risk was 11.6% among BRCA1/2 carriers between ages 40 and 50 years.

The 10-year cumulative risk for mutation carriers with a first tumor that was triple-negative was 18.9%. This risk was 11.2% among carriers with a non-triple-negative first tumor.

The researchers isolated germline DNA from formalin-fixed paraffin-embedded tissue and used these samples to test for the prevalent pathogenic BRCA1 and BRCA2 mutations in The Netherlands.

Events were defined as second primary breast tumors in the contralateral breast which were diagnosed more than 3 months after the diagnosis of the initial cancer.

"If these results are confirmed in other studies, guidelines about treatment decisions and screening for follow-up may take into account these high risk subgroups to provide even better information and counseling for BRCA1/2 mutation carriers," van den Broek said.

Earn CME this spring at the HemOnc Today Breast Cancer Review & Perspective meeting to be held March 23-24, 2012 at the Hilton San Diego Bayfront. See details at HemOncTodayBreastCancer.com.

For more information:

van den Broek AJ. Abstract #S4-2. Presented at: 2011 CTRC-AACR San Antonio Breast Cancer Symposium; Dec. 6-10, 2011; San Antonio.

Follow HemOncToday.com on Twitter.