SOURCE: University of Colorado Anschutz Medical Campus, news release, March 21, 2016
TUESDAY, March 22, 2016 (HealthDay News) -- Race and income differences may affect treatment for some patients with early stage breast cancer, a new study suggests.
The study looked at women with estrogen-receptor-positive breast cancer, a type of cancer that's fueled by the hormone estrogen. Researchers found that black patients and people with low incomes were less likely to receive a genetic test that's used to predict the aggressiveness of the disease.
"We meant this study as a kind of state of the union for the use of this test. What we found were some pretty stark disparities along socioeconomic and racial lines," said the study lead author, Dr. Jagar Jasem, an investigator at the University of Colorado Cancer Center.
The test is called the 21-Gene Recurrence Score Assay. It predicts the likelihood that a woman's cancer will come back using a scale of 1 to 100. A high score -- 31 or more -- suggests that it's likely the cancer will come back. A low score -- below 18 -- suggests that the cancer is unlikely to recur, researchers said.
If the cancer isn't likely to come back, the risks of chemotherapy outweigh its potential benefits, the study authors said. On the other hand, patients with a high score would likely benefit from chemotherapy -- despite its risks -- because without chemotherapy, their cancer is likely to return. Women with an intermediate score -- 18 to 30 -- may also benefit from chemotherapy, the researchers said.
Jasem and his colleagues reviewed more than 143,000 patient records for the study.
They noted that black women with early stage, estrogen-receptor-positive breast cancer who were given the test had a greater chance of having an aggressive tumor that would respond to chemotherapy. However, black patients were less likely to receive the test, the researchers said.
What's more, the study found that when black women were tested, overtreatment was still a risk. The researchers said black patients were more likely to undergo chemotherapy even if they had a low score on the test.
"We show that doctors are absolutely using this test to decide who gets chemotherapy along with their treatment. In fact, of all the variables we explored, this test was most strongly associated with the chance that a patient goes on to receive chemotherapy," Jasem said in a university news release.
"But what we show is that the treatment of minority and low-socioeconomic patients is more likely to be disconnected from these test results," he said.
Patients treated at community centers and those with Medicaid and Medicare were also less likely to be tested, the study showed.
The study was published March 21 in the Journal of Clinical Oncology.
The U.S. National Cancer Institute provides more information on breast cancer.