Tuesday, December 25, 2012

BRCA testing impact on ovarian cancer prevention revealed

BRCA testing impact on ovarian cancer prevention revealed

Published on December 24, 2012 at 9:15 AM

By Lynda Williams, Senior medwireNews Reporter

Research shows that women without a confirmed BRCA mutation are choosing to undergo screening or surgery to prevent ovarian cancer, despite little evidence to support their use in this population.

After BRCA mutation testing and genetic counseling, a significant proportion of women with an uninformative result underwent risk-reducing salpingo-pophorectomy (RRSO; 12.3%), screening transvaginalultrasonography  (TVUS; 37.3%), or serum cancer  antigen (CA)-125 testing (33.8%).

"For most women with uninformative BRCA results, RRSO and ovarian cancer screening may not be appropriate, barring strong family histories of ovarian cancer," caution Gabriel Mannis (University of California, San Francisco, USA) and co-workers in the Archives of Internal Medicine.

The team followed up 1077 women for a median of 3.7 years after genetic counseling and BRCA testing. A positive BRCA test was confirmed in 18.7% of the patients, 9.6% had a true-negative result, and 71.8% had an uninformative test.
Compared with an uninformative result, a positive BRCA test strongly and significantly predicted the likelihood a woman would undergo RRSO (odds ratio [OR]=28.1), TVUS (OR=9.5), and serum cancer antigen (CA)-125 screening (OR=13.0).

This is in line with guidelines from the American College of Obstetricians and Gynecologists that recommend RRSO in BRCA-positive women aged over 40 years or after childbearing is complete, Mannis et al observe.

Conversely, a true-negative result was associated with a significantly reduced risk for RRSO (OR=0.1), TVUS (OR=0.2), and serum CA-125 screening (OR=0.3) compared with an uninformative test.

With a low 1-2% lifetime risk for ovarian cancer and the potential harm associated with false-positive test screening results, the team says these findings are in line with the knowledge that there is "insufficient evidence to recommend ovarian cancer screening for women with true-negative BRCA results."

Recognizing that the long-term risk for ovarian cancer in women with an uninformative BRCA test result is unknown, the researchers comment: "Because this population likely represents a heterogeneous group… it is possible that certain subgroups, such as women with strong family histories of ovarian cancer, may be at higher-than-average risk.
"In the face of such uncertainty, patients and physicians may opt to obtain screening tests despite the absence of evidence-based guidelines and the questionableefficacy. of these tests."

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