Sometimes, it’s not so much the disease as the risk of the disease that influences treatment.
The largest study to date looking at how genetic testing and counseling affects patients’ treatment decisions has found that women newly diagnosed with breast cancer who test positive for BRCA1 and BRCA2 mutations are twice as likely as non-carriers to request a prophylactic bilateral mastectomy.
The study also suggests that genetic counseling “can have a significant impact” on the kinds of treatment decisions made by these high-risk patients, Marc Schwartz, associate professor of oncology at Georgetown University’s Lombardi Cancer Center and lead study author, said in a statement.
Lastly, the study results may spur more physicians to offer genetic testing and counseling for high-risk patients with this and other diseases.
“We’re not ready to recommend widespread ... rapid genetic counseling and testing at the point of diagnosis until we evaluate long-term psychosocial and medical outcomes of counseling and testing in a true pay-for-services clinical setting,” Schwartz said in a statement this week. “However, … high-risk breast cancer patients should be informed about the availability of genetic counseling and testing so that they can make informed choices about their cancer treatment.”
It is widely known that women with breast cancer in one breast who test positive for BRCA1 and BRCA2 mutations have a “greatly elevated risk” of developing cancer in the opposite breast for at least 10 years following the original diagnosis. As a result, some — but not all — oncologists and cancer centers offer genetic counseling concomitantly with genetic testing.
To learn whether this kind of counseling has an effect on treatment options, Schwartz and colleagues provided free genetic testing and counseling to 167 patients newly diagnosed with breast cancer. Test results were ready in around two weeks.
Of the 167 women, 31 tested positive for BRCA1 or BRCA2 mutations. The remaining 136 had no mutation, or had a “mutation of unknown significance,” Schwartz reported in the April 5 Journal of Clinical Oncology. Of the 31 who tested positive for the mutations, 48 percent chose to undergo “an immediate double mastectomy.” By comparison, 24 percent of women with no mutation or one of unknown significance took that step.
The researchers stressed, however, that while a positive test result “strongly influenced a woman’s treatment choice,” their physician’s recommendation “was the single most important factor affecting her decision.” According to Schwartz, patients whose physicians “recommended” genetic testing or “considered” a double mastectomy were “significantly more likely to choose the procedure — a finding that underscores the complementary role of genetic counseling and testing, and shared decision-making between patients and physicians.”
Schwartz and his colleagues also noted that “many” of the patients who had negative genetic test results and took the double-mastectomy route “had either a strong family history of breast cancer or other risk factors,” including multiple previous biopsies in the opposite breast.
Mary Daly, a medical oncologist at the Fox Chase Cancer Center in Philadelphia, said the study “provides compelling evidence” that women at high risk for breast cancer who are given access to genetic counseling “will incorporate the test information into primary treatment decisions.”
Writing in an accompanying editorial, Daly adds: “Given the high rates of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers, the choice to undergo a bilateral mastectomy rather than breast-conserving surgery could ultimately translate into improved survival for this population of patients.”
But Schwartz and colleagues warned that women still face obstacles to getting the information they need to make this choice. “Despite increased access to genetic testing in the United States, patients still face significant delays in getting an appointment to see a genetic counselor and obtaining insurance approval,” the Lombardi researchers said in the statement.
“While rapid testing is available in some locations, patients still need to see a genetics counselor and obtain insurance approval, which can delay treatment decisions,” they went on. “Moreover, rapid tests are much more expensive than regular tests, and often not fully covered by insurance.” According to Schwartz, costs for genetic tests range from $415, which looks for a trio of mutations in Ashkenazi Jews, to almost $3,000 for a full BRCA1/2 test.
Daly noted that these kinds of “barriers … should not deter the oncology community from encouraging widespread access to genetic counseling and testing for high-risk cancer patients. …”
Schwartz himself conceded that his study has limitations. “The group in our study was a pretty select group: newly diagnosed breast cancer patients who were identified as being high risk,” he said. “And I think this shows that offering and actually doing genetic counseling and testing in that post-diagnostic period is feasible, so that patients were able for the most part to get their counseling. Those who chose to get genetic tests were able to get genetic tests back in time to make definitive surgical treatment decisions.
“I think the second thing is that it showed that counseling and testing for those who are interested should be discussed and offered to high-risk patients in the post-diagnostic period,” he went on.
Asked if he thought the results of this study would spur more physicians to offer molecular diagnostics tests to more patients, he said that some factors of the trial would have confounded attempts to glean that kind of information. For example, he said that since his study offered genetic testing and counseling for free, women participated in the counseling and testing “even in cases where they might not be interested in using the results for their treatment decision making.”