Negative tests for BRCA genes don't always ease fears, study says
December 19, 2012 | by Roberta Nichols
Testing negative for the BRCA genetic mutations linked to breast and ovarian cancer can put many women’s minds at ease, allaying fears they face an increased risk of the diseases. But not all women are reassured.
Some women who were identified as not having the BRCA mutations undergo additional screening and risk-reducing procedures to prevent ovarian cancer – despite limited evidence that these interventions are actually effective, according to a new study published online Monday in the Archives of Internal Medicine.
Although the lifetime risk of developing ovarian cancer is only 1 to 2 percent in the general population, women with BRCA mutations have decidedly different odds.
A cumulative lifetime risk of developing ovarian cancer is approximately 40 percent in BRCA1 carriers and approximately 20 percent in BRCA2 carriers, according to the study. “In light of this, there has been significant interest in defining the role of ovarian cancer screening in individuals who might be at higher-than-average risk,” the researchers wrote.
Previous studies have documented the behaviors of BRCA mutation carriers, but less is known about the behaviors of non-BRCA carriers, according to first author Gabriel N. Mannis, M.D., of the University of California, San Francisco.
In the latest study, researchers surveyed 1,077 women who had received genetic counseling and BRCA testing. The women had undergone the testing a median of 3.7 years earlier.
Mannis and his colleagues assessed the prevalence and post-test predictors of screening interventions, as well as interventions meant to reduce risk. They found that even many women who tested negative for the mutations subsequently underwent vaginal ultrasound or blood serum tests. Some even underwent salpingo-oophorectomy (RRSO) – the surgical removal of an ovary and a fallopian tube.
“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,” according to the study.
“The study by Mannis et al. shows that genetic testing, even if negative, does not always allay deep-seated fears of cancer,” said Victor Grann, M.D., M.P.H., and Maxine Ashby-Thompson, M.P.H., of Columbia University, in an accompanying commentary. “The challenge of the field is to identify persons needing additional or different treatment without scaring those who do not into additional interventions.”
But fears are personal, and often not easily mitigated, as one City of Hope researcher points out.
“I think that the main point of the study is that individuals have their own feelings about the risk of developing ovarian cancer – and that the idea that they were screened possibly makes this presumed risk higher, even in the situation where the scientific information does not support these conclusions,” said Robert J. Morgan, M.D., co-director, Gynecological Oncology/Peritoneal Malignancy Program at City of Hope (who was not involved in the study).
“This emotional reaction can lead to increased testing including blood tests and ultrasound tests, both at the request of the patients and due to zealousness of the physician,” continued Morgan, who is also associate director for medical education, medical oncology and therapeutics research.
“Medicine isn’t only a science, it is also an art,” Morgan said, “and each of us approaches life and cancer risks in our own individual ways.”