by Lisa Rezende, PhD
One of the challenging questions facing women who carry mutations in BRCA1 or BRCA2 genes is the age when risk-management for hereditary cancer should begin. Cancer risk assessment is an evolving area of medicine and great strides have been made, but there is still no way to predict the exact risk for cancer and at what age it is most likely to develop. This has a profound impact on young, high-risk women. Expert guidelines for high-risk women recommend breast screening with MRI and mammograms beginning at age 25 or 10 years earlier than the youngest onset of cancer in a family. But other factors beyond family cancer history and having a BRCA mutation impact the age of breast cancer diagnosis and the optimal time to begin breast screening is not well established. Prior research suggested that high-risk women from earlier generations had a later onset of breast cancer than women from more recent generations. New research seems to confirm this trend.
In a study of 106 families with hereditary breast and ovarian cancer (HBOC), the average age at cancer diagnosis was 7.9 years younger in the current generation when compared to the previous generation. This finding of the younger generation being diagnosed with cancer at younger ages than the older generation held true when researchers classified the families by mutation type (BRCA1 vs BRCA2), type of cancer (family history of breast cancer only vs. family history of breast and ovarian cancers), or who the mutant gene was inherited from (mother's side of the family vs. father's side of the family).
While the trend towards earlier age of diagnosis for later generations is statistically significant, more research is needed before the exact number of years earlier is confirmed. The researchers acknowledge that in many cases the BRCA or BRCA2 mutational status of the older generation must be inferred from the mutational status of the daughter or granddaughter because genetic testing was not available when this older generation was diagnosed. Furthermore, obtaining accurate medical histories, including age at diagnosis, is not always possible. Finally, detection methods are much more powerful today, and women with known mutations in BRCA1 and BRCA2 are screened more frequently that previous generation, allowing for earlier (hence younger) diagnosis. Given these factors, the actual difference in age of cancer developing might be less than 7.9 years.
Current guidelines recommend that women from families with HBOC begin regular screening for breast cancer at age 25 or 5-10 years earlier than the earliest age of diagnosis in their family. The researchers recommend that further research be done before changing guidelines as to when young women with BRCA1 or BRCA2 mutations should beginning regular screening for breast cancer.