In a new study, researchers from the Stanford University School of Medicine said that too few women with ovarian cancer are getting genetic testing for cancer-related mutations.
“All women with ovarian cancer at time of diagnosis, not at recurrence, but at the time of diagnosis, should undergo genetic testing regardless of family history, the patient’s age and histology,” says Dr. Ursula Matulonis, Chief of the Division of Gynecologic Oncology at Dana-Farber Cancer Institute.
Read MoreResearchers used data from the National Cancer Institute’s Surveillance, Epidemiology and End Results Program, which tracks cancer diagnoses and outcomes in large populations across the United States. After linking that data to data from four genetic testing laboratories, they found that out of 6,001 patients with ovarian cancer, 30.9 percent underwent any genetic testing.
According to Dr. Matalonis, women should be tested regardless of any other factors. “I can say that again, it’s really important that all women with ovarian cancer be tested at the time of diagnosis regardless of her age, the type of ovarian cancer that she has, as well as her family history,” she says. “We [even] know that women who have no family history of ovarian cancer still can have the BRCA mutation, just because of small families and other reasons.”
If a woman does have the BRCA mutations, their family members may also be affected.
About 1.3 percent of women in the general population will develop ovarian cancer sometime during their lives. About 44 percent of women who inherit a harmful BRCA1 mutation and about 17 percent of women who inherit a harmful BRCA2 mutation will develop ovarian cancer by the age of 80, and that population accounts for approximately 15 percent of invasive ovarian carcinomas.
Almost one-third of women with hereditary ovarian carcinoma have no close relatives with cancer, and 35% of women with hereditary ovarian carcinoma are older than 60 years at diagnosis.
The study also included information on breast cancer and genetic testing. Out of 77,085 women with breast cancer, 24.1 percent received genetic testing, but guidelines for genetic testing for breast cancer patients have been less expansive than for ovarian cancer, so the discrepancy between guidelines and real-world application is less defined.
For women with a harmful BRCA1 mutation, the likelihood of developing breast cancer in the other breast within 20 years is about 40 percent. The likelihood for women with a harmful BRCA2 mutation is about 26 percent.
Dr. Elizabeth Comen on when to consider genetic sequencing for breast cancer
Researchers also described a disparity in rates of ovarian cancer patients who received genetic testing according to race. Nearly 34 percent of non-Hispanic white women received genetic testing after their diagnosis, while only 22 percent of black women and 24 percent of Hispanic women were tested.
Insurance also played a role, with about 20 percent of women with medicare getting tested, while about 34 percent of women with other forms of insurance received testing. “Testing prevalence decreased to about 20 percent in areas where residential poverty equaled or surpassed 20 percent, and it was about 38 percent in regions where the poverty level was less than 10 percent,” says the study.
Among women with breast cancer who did receive genetic testing, 14.5 percent of non-Hispanic white patients had mutation variants of unknown significance. By contrast, 28.5 percent of african american patients, 26.6 percent of Asian patients, and 19.3 percent of hispanic patients had mutations of unknown significance, suggesting a need for more information on genetic mutations for minority groups.
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