A genetic test that helps doctors determine how best to treat breast cancer—and whether chemotherapy is likely to help—is significantly more likely to be administered to white women than blacks or Hispanics, a Yale study has found.
The test, called Oncotype Dx (ODx), uses gene expression to gauge how early-stage breast cancer is affecting patients’ gene activity. It uses the information to determine how likely cancer recurrence would be, and physicians and their patients can use that knowledge to decide how to proceed with treatment.
Yale researchers retrospectively analyzed a group of more than 8,000 Connecticut women who were diagnosed with hormone receptor positive breast cancer between 2011 and 2013, and found “significant racial and ethnic disparities in use of this new gene test,” said study leader Dr. Cary Gross, a member of Yale Cancer Center and professor of medicine and epidemiology at Yale School of Medicine.
“It reinforces that, at the same time we are investing in developing new treatments and new testing strategies and we’re promoting them with great excitement, we really need to double-down our efforts to eliminate disparity,” Gross said.
The nonprofit National Comprehensive Cancer Network (NCCN) has guidelines identifying instances in which ODx is recommended. Among the Connecticut women for whom the test was recommended under the guidelines, Yale researchers found 51.4 percent of white women received ODx, compared with 44.6 percent of black women or 47.7 percent of Hispanic women.
The study also found disparity among women for whom NCCN guidelines did not recommend ODx. In that group, 21.2 percent of white women, 9 percent of black women and 9.7 percent of Hispanic women received it.
The disparities are troubling but not surprising, said Dr. K. M. Steve Lo, a hematology oncologist and breast cancer expert at Stamford Hospital’s Dorothy Bennett Cancer Center. The study’s findings mirror similar trends, he said, which show minority women have less access than white women to mammography, radiation treatments and breast conservation. Minority women also are more likely to die from breast cancer.
“It’s part of the overall problem with our health care system,” Lo said. “Minority women are less insured, underinsured, and have more out-of-pocket expenses to put out in one way or another. As a result, there will be less use of technology across the board. It needs to change but, unfortunately, I don’t see a movement toward that in the near future. It’s a systemic problem, and it’s a problem that we as a society need to address.”
Given that racial disparities pertaining to breast cancer have long existed, Gross said there is a risk that minority women could be “getting left behind” as new tests and tools are developed.
“That’s why we did this study, to see whether that was the case,” he said. His team’s findings recently were published in the Journal of the National Comprehensive Cancer Network.
Having access to ODx can greatly impact women’s outcomes, Gross said. Even after a biopsy or tumor removal, he said, “it’s still difficult to know which patients are at higher risk for their cancer coming back again. There are many, many subtypes of breast cancer. [ODx] takes some of the guesswork out of it.”
The test has become the standard of care for certain types of early-stage cancer, Lo said.
“This test is very, very important,” Lo said. “This is a test we use all the time.”
It helps physicians “narrow down those women who really do benefit” from treatments like chemotherapy, he said. That is crucial, he added, because it means many women who would not benefit from chemotherapy no longer are subjected to the process, the expense and the side effects.
ODx most frequently is used on women who have stage 1 cancer that has not spread to the lymph nodes, Lo said, but it’s likely it will be used on women whose cancer has attached to lymph nodes.
In light of the study’s findings, Gross’ team plans to examine data from a broader group of women to see why the ODx disparities exist. Researchers will look at whether women are more or less likely to get the test depending on which hospital treats them, or whether there are disparities within hospitals.
Gross also said research should be done to determine if the test’s $4,000 price tag—though covered by many insurance companies—is a barrier to some patients, and more breast cancer patients should be educated about NCCN guidelines and recommendations.