For this study, part of Gonzalez-Angulo's ongoing laboratory project, Molecular Characterization of Triple Negative Breast Cancer, the researchers sent both tumor and normal tissue of 77 women with triple negative disease to Myriad Genetics Inc. to identify germline (inherited) and somatic (in tumor only) BRCA mutations. Of those 77 patients, 15 (19.5 percent), were found to have mutations (14 germline, one somatic) -12 (15.6 percent) with BRCA1 and three (3.9 percent) with BRCA2.
The triple negative breast cancer patients were treated at MD Anderson between 1987 and 2006, and all but one received the same adjuvant chemotherapy regimen. The median follow-up was 43 months. The five-year relapse-free and five-year overall survival of the patients with either BRCA mutation, was 86,2 percent, and 73.3 percent, respectively, compared to 51.7 percent and 52.8 percent, respectively, in patients lacking mutations.
The researchers were surprised by the findings, however, Gonzalez-Angulo notes that prior studies conducted were case-controlled looking at BRCA mutations carriers with all types of breast cancer. The MD Anderson study is the first to look exclusively at women with triple negative breast cancer, an unselected population.
Also surprising, the incidence of BRCA mutations in the triple negative breast cancer population was higher than expected, said Gonazlez-Angulo.
"It was interesting to find that a good portion of these women were not sent to genetic counseling - some didn't meet the criteria to be sent for testing, however they still had BRCA mutations," said Gonazlez-Angulo. "Perhaps we need to lower our threshold for patients with triple negative breast cancer for genetic counseling and to assess f
|Contact: Laura Sussman|
University of Texas M. D. Anderson Cancer Center