Women who inherit BRCA gene mutations develop cancer earlier than their ancestors

(Press-News.org) A new analysis has found that women who develop certain hereditary cancers develop them at earlier ages than women in the previous generation. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the results point to the importance of tracking younger ages of cancer diagnosis to determine when to provide counseling, screening, and treatment services.

Women who have mutations in the BRCA genes have a high risk of developing breast and ovarian cancers at young ages. Mutations in these genes are often inherited, so multiple family members may be diagnosed with these cancers at young ages. Researchers have wondered: if a woman develops BRCA-related cancer at a certain age, will female relatives in the next generation develop it even earlier?

To investigate, Jennifer Litton, MD, of the University of Texas MD Anderson Cancer Center in Houston, and her colleagues looked at trends in the age of cancer diagnosis between generations in families with a history of BRCA-related cancer. Of 132 women in the study who had breast cancer and BRCA gene mutations, 106 had a family member in the previous generation who was diagnosed with a BRCA-related cancer (either breast or ovarian cancer).

When evaluating age differences between generations in each family, the researchers found that the average age of cancer diagnosis in the second generation was 42 years, compared with 48 years in the first generation. A separate more inclusive analysis of the entire study group revealed that the expected age-of-onset of cancer went down by 7.9 years from the first generation to the second.

The results suggest that women who inherit BRCA gene mutations develop cancer at younger ages than women in the previous generation.

Guidelines by the National Comprehensive Cancer Network suggest initiating screening for hereditary breast cancer at age 25 years or five to ten years earlier than the age of earliest diagnosis in a family. "Our research tells us that we need to continue to initiate screenings at least ten years prior to the earliest cancer diagnosis," said Dr. Litton. "Also, because we do not have the BRCA mutation status of affected individuals from previous generations, when testing may not have been available yet, it is vital that we continue to collect family information," she added. Monitoring for shifts in the age of cancer diagnosis in future generations will help caregivers and patients decide when to consider counseling, screening, and treatments.

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