(RxWiki News) Sure, if a woman has a high risk from family history and tests positive for a mutated gene, preventive measures are good. But excessive testing may be unnecessary for everyone else.
A recent study surveyed women who had been tested for a gene that, when mutated, can play a role in ovarian cancer.
Even women with negative results were highly likely to continue with ovarian cancer screening methods, some of which included surgical removal of the ovaries and fallopian tubes.
"Talk to your doctor about cancer screening options."
Gabriel N. Mannis, MD, from the Division of Hematology/Oncology in the Department of Internal Medicine at the University of California at San Francisco, led the research team. BRCA1 and BRCA2 are tumor-suppressing genes. Mutations of these genes have been linked to ovarian and breast cancer. Ovarian cancer from BRCA mutations is believed to have a hereditary element.
In the general population, ovarian cancer risk is only about 1-2 percent. In women with BRCA mutations, ovarian cancer risk is around 40 percent for BRCA1 and around 20 percent for BRCA2.
For the study, 1,077 women who underwent testing for BRCA genes at one of two hospitals were followed for several years. A total of 19 percent of the women had BRCA mutations, 10 percent did not have the mutated BRCA gene and 72 percent had inconclusive results.
Preventive measures were taken in many cases, including risk-reducing salpingo-oophorectomy (RRSO), which is the surgical removal of both ovaries and fallopian tubes, vaginal ultrasounds and serum cancer antigen 125, which is a blood test.
A total of 19 percent of eligible women and an additional 12 percent of women with inconclusive results had their fallopian tubes and ovaries surgically removed. Of the women with inconclusive results, 34 percent had serum cancer antigen 125 screening done and 38 percent had vaginal ultrasounds to check for ovarian cancer.
Researchers found close to 70 percent of BRCA positive women, 30 percent of women with inconclusive results and 10 percent of women with BRCA negative test results did ovarian cancer screening.
Authors concluded, “Result of BRCA testing strongly predict RRSO and ovarian cancer screening.”
“Use of RRSO and ovarian screening was reported in a sizable percentage of non-BRCA carriers despite insufficient data to determine the effectiveness of these interventions.”
In a related commentary, Victor Grann, MD, MPH, from the College of Physicians and Surgeons at Columbia University in New York, talked about why further screening or surgery for women without BRCA is costly.
“The cost of preventive screening and treatment for BRCA1/2 mutations accounts for approximately $800 million of more than $8 billion spent each year for treatment of breast and ovarian cancers.”
The additional cost for women with inconclusive BRCA test results to undergo vaginal ultrasounds or serum cancer antigen 125 testing three times in three years provides inconclusive benefits.
Dr. Grann said, “[T]he study by Mannis et al shows that genetic testing, even if negative, does not always allay deep-seated fears of cancer. The challenge of the field is to identify persons needing additional or different treatment without scaring those who do not into additional interventions.”
BRCA1/2 genetic testing in the US is all done by sending a blood sample to Myriad Genetics. They can test a portion of the DNA for around $300 or the complete DNA map for around $3,000.
No clear benefit was found for women who had negative or inconclusive BRCA tests and continued to have additional screening or RRSO.
This study was published in December in the Archives of Internal Medicine. Funding was supported by the UCSF Clinical Translational Science Institute, the Center for Translational and Policy Research in Personalized Medicine, the Avon Foundation, the Bay Area Breast Specialized Program of Research Excellence and the Doris Duke Charitable Foundation. No conflicts of interest were reported.