The MINDACT phase 3 clinical trial involved nearly 6,700 women at 111 medical centers in nine countries.
In the clinical trial, researchers sorted breast cancer patients into four groups, based on whether MammaPrint testing or traditional clinical assessment recommended chemotherapy (from a tool that oncologists use called Adjuvant! Online).
The shocking results of the long awaited MINDACT clinical trial are in.
- Many breast cancer patients have been receiving chemotherapy treatments they didn’t need.
- And that chemotherapy made no difference in their survival.
- After surgery to remove their tumors, early-stage breast cancer patients (0-3 positive nodes) with a MammaPrint score recommending against chemotherapy had a 95% survival rate.
- “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.
“This study is telling us in a very clear way we can spare many women chemotherapy,” said Baselga, chief medical officer of Memorial Hospital at Memorial Sloan Kettering Cancer Center, in New York City.
- MammaPrint reduced chemotherapy prescriptions by 46% among the more than 3,300 patients in the trial categorized as having a high risk of breast cancer recurrence based on common clinical and pathological criteria, the researchers said.
- Further, just over 2,700 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 chemo or not, the researchers said.
- “If we can select those patients that don’t need chemotherapy, unneeded treatment can be avoided and we will be one step closer to making sure treatment for breast cancer is tailored to the individual,” said Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City.
- Young women have been more likely to receive chemotherapy in standard breast cancer care, even though it can destroy their fertility and leave them open to long-term health problems, Vogel said.
- “In my training, if you had a young woman with breast cancer, she got chemotherapy,” Vogel said. “But now we can be selective, and we know there’s a very large number of young women with small hormone-responsive tumors who do not need chemotherapy.”