Genetic test can help doctors determine who can safely avoid treatment after surgery
MONDAY, April 18, 2016 (HealthDay News) — Many breast cancer patients receive chemotherapy they don’t need, according to the results of a long-awaited clinical trial presented at the annual meeting of the American Association for Cancer Research, held from April 16 to 20 in New Orleans.
The clinical trial involved 6,693 women at 111 medical centers in nine countries. The team used the MammaPrint test, which looks at a panel of 70 genes within the tumor itself to assess its aggressiveness and the odds it will come back without chemotherapy. In the clinical trial, researchers sorted breast cancer patients into four groups, based on whether MammaPrint testing or traditional clinical assessment recommended chemotherapy.
MammaPrint reduced chemotherapy prescriptions by 46 percent among the 3,356 patients in the trial categorized as having a high risk of breast cancer recurrence based on common clinical and pathological criteria. Further, 2,745 patients who had a low MammaPrint risk score but a high clinical risk score wound up with a 94.7 percent five-year survival rate, whether they got chemotherapy or not, the researchers said. After surgery to remove their tumors, breast cancer patients with a MammaPrint score recommending against chemotherapy had a 95 percent survival rate, coauthor Laura van ‘t Veer, Ph.D., the test’s inventor, told HealthDay.
“That’s very high, and we showed that it doesn’t differ between those who are treated and those who are not treated by chemotherapy,” said van ‘t Veer, leader of the breast oncology program at the University of California, San Francisco, Diller Family Cancer Center.
The study was partially supported by Agendia, which markets the MammaPrint.
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