Purpose: Breast cancer in BRCA2 gene mutation carriers differs from BRCA1-associated breast cancer or so-called sporadic breast cancer in clinical features and behavior. These differences may be of importance for the prevention, screening, and ultimately treatment of breast cancer in women with such germline mutations.
Methods: We reviewed the few studies that have reported on survival in patients with BRCA2-associated breast cancer. In this article we discuss why family history is no substitute for hereditary breast cancer with regard to studying survival and possible reasons why studies using family history yield contradictory results, why BRCA2-associated breast cancer should be considered a unique entity, and what methodological problems may exist, especially with regard to family-based studies.
Results: Five studies have reported on survival in BRCA2-associated breast cancer. Two studies showed a statistically significant worse survival for BRCA2 patients, but the patients from one of these studies were later claimed to have a trend toward better prognosis when controls were matched for age and year of diagnosis. The other study found that the unfavorable prognosis of BRCA2 patients was, to a great extent, due to a worse stage of the disease at time of diagnosis. The remaining three studies showed no significant effect of germline BRCA2 mutations on survival. The numbers of BRCA2 patients investigated in these studies were 42, 20, 23, 28, and 54 patients. Five-year overall survival in these patients varied from 65% to 74%.
Conclusion: No definite conclusion can be made with regard to the prognosis of BRCA2-associated breast cancer, but large differences in comparison with sporadic breast cancer are not likely to exist. Breast cancer caused by BRCA2 mutations is also a distinct entity with its own features when compared with BRCA1-associated breast cancer. In contrast with BRCA1-associated breast cancer, BRCA2 tumors tend to be more often steroid receptor-positive.