(Reuters Health) - Many women who test negative for gene mutations that heighten the risk of ovarian cancer still get their ovaries removed despite a lack of evidence that it reduces the risk of dying, says a new study.
"A higher number than expected went through with the surgery, and it probably has to do with doctors in the community not having enough information on their patients' risk levels," said Dr. Gabriel Mannis, the study's lead author.
According to Mannis and his colleagues, who published their study in the Archives of Internal Medicine on Monday, the average woman's risk of developing ovarian cancer is about 2 percent, but women with BRCA1 and BRCA2 gene mutations have a 40 percent and 20 percent risk, respectively.
For women that test positive for the gene mutations, the American Congress of Obstetricians and Gynecologists (ACOG) says, if they choose to have their ovaries removed, it should be when they are done having children and near 40 years old.
There are no guidelines, however, on ovary removal and screening for women whose blood tests don't show the gene mutations but who may still be at an increased risk of cancer based on their family's medical history.
"We don't have a clear sense of what their risk level is, or what the role of screening should be," said Mannis, of the division of oncology at the University of California, San Francisco.
For the new study, the researchers surveyed women at two hospitals about 4 years after they were tested for the gene mutations to see if they decided to be screened or have their ovaries removed.
Of 1,077 women surveyed, about 19 percent tested positive for a BRCA mutation, about 10 percent had no mutation, and the rest had unclear results.
The researchers found that about 70 percent of the women who tested positive for a mutation had their ovaries removed by the time they took the survey.
But, despite a lack of evidence that they should have their ovaries removed, about 12 percent of the women with unclear results still had the surgery.
OVARIAN CANCER SCREENING
The researchers also found that despite the U.S. Preventive Services Task Force recommending against screening for ovarian cancer in women without the gene mutations, about 20 percent of women whose test results didn't clearly show the mutations still ended up getting screened in the year before taking the survey.
In a previously published study, women screened annually for ovarian cancer were no less likely to die from the disease than those who didn't get regular screening (see Reuters Health article of Sep. 10, 2012. reut.rs/QAmMdk).
Aside from not being shown to help, the tests are also imperfect, said Dr. Jed Delmore, chair the Gynecologic Oncology Sub-committee for ACOG.
"I can simply say that as of today we don't have a good screening," said Delmore, of the University of Kansas School of Medicine in Wichita.
"At this point if doctors are going to proceed with screening in this group of women, there needs to be a conversation that we don't really know if this will prevent you from dying sooner of ovarian cancer or that it may come back as a false positive," said Mannis.
In that previous study, about one in ten screened women had a false positive result, and of those a third had one or both ovaries removed.
That means some women had both ovaries removed even though they were not at an increased risk for cancer, which needlessly put them in danger of a complication and forced them into menopause.
Plus, the removing an ovary can cost over $3,000.
Delmore told Reuters Health that it seems like an intermediate ground has been reached with a majority of BRCA-positive women having surgery to reduce their risk, and fewer BRCA-negative women having it.
He agreed with Mannis that doctors need to be honest with their patients about the limitations of today's screenings and treatments.
"We have pretty solid information for women who are BRCA positive and clearly BRCA negative," he said. "It's just that group in the middle."
Mannis told Reuters Health that the next step would be to identify that group's risk levels, but both he and Delmore said that won't be easy.