Breast cancer risk varies amongst BRCA gene carriers

by Elaine on January 10th, 2008

Breast awareness and regular checking are important in early detection of breast cancer

Further to my articles on the BRCA breast cancer genes, an American and Danish study has found the risk of developing cancer amongst carriers of the BRCA1 and 2 breast cancer gene mutations varies greatly. The risk of breast cancer in BRCA1 and BRCA2 mutation carriers has been examined in many studies, but relatively little attention has been paid to the degree to which the risk may vary among carriers. This knowledge of risk is important when deciding cancer treatment and prevention.

The study lead Dr Colin Begg of the Memorial Sloan-Kettering Hospital in New York genotyped 2,098 women for mutations in BRCA1 and 2 genes. The women were participants in the Women’s Environmental Cancer and Radiation Epidemiology (WECARE) study and had cancer either in one breast only (unilateral) or in the second breast after having had it in the first breast (contra-lateral). They were tested to see if they were gene mutation carriers and whether a first degree relative (mother, sister, daughter) had been diagnosed with breast cancer.

The findings indicated that there was a wide variation in breast cancer risk amongst carriers of BRCA 1 and BRCA 2. 5.2% of women with unilateral breast cancer carried one or both of the faulty genes. 15.3% of women with contra-lateral breast cancer carried one or both of the faulty genes. The risk of developing breast cancer amongst first degree relatives was significantly higher the earlier in age of the initial diagnosis. The risk was higher for relatives of women with contra-lateral breast cancer by a ratio of 4 to 1.

The authors wrote “Genetic testing for BRCA2 and BRCA2 mutations is not currently recommended as part of routine cancer screening, but in the future, as technology advances and costs come down, it could become part of routine population wide genetic screening and form a cornerstone of tailored risk reduction programmes.For this reason, it is important that risk estimation is accurate and the sources of risks correctly identified as they will be important factors in the clinical management of women who carry the BRCA1 and BRCA2 mutations”.For further information on the study, please click on the following