While the concept of precision medicine still has a futuristic ring to it, researchers at the University of Michigan are showing how physicians in everyday practice can use biomarker tests to make significantly more personalized decisions regarding which breast cancer patients may require chemotherapy to ensure recurrence doesn't happen, and which patients are probably better off without.
"The idea of precision medicine is to give patients the treatments that are the most likely to help and avoid needless side effects," Christopher Friese, study author and professor at the University of Michigan School of Nursing, said in a statement.
The test is called the 21-gene recurrence score assay (RS) and it looks at 21 genes that are known to increase the risk of cancer recurrence. The goal is to avoid chemotherapy in patients who are at low risk because they most likely won’t benefit from it and to make sure that chemotherapy is recommended for women at high risk.
The researchers surveyed 3,880 women who were treated for breast cancer in 2013 and 2014 in California and Georgia. A total of 1,527 patients with early-stage breast cancer responded to the survey and 778 received the test.
They found that 47.2 percent of the patients with RS scores received a recommendation against chemotherapy and 40.6 percent received a recommendation for it. Those results correlated with the professional guideline recommendations.
However, they did find that about 13 percent of the patients whose lymph nodes were positive for breast cancer were given the test — even though there’s no evidence they would have benefitted from the test or the outcome.
The researchers evaluated registry and laboratory data and found that 60 percent of the patients accurately recalled receiving the test.
"This suggests that while precision medicine for breast cancer has left the station, we have left a few women behind," said Friese. "There's opportunity in the oncology community to improve how we explain to women the purpose of these tests, how to interpret the results, and what the results mean for their breast cancer treatment."
In addition, almost two-thirds thought the test was helpful in shifting their opinion for or against chemotherapy.