A genetic test called MammaPrint determined that nearly half the women slated for chemotherapy based on standard clinical assessments didn’t really need to undergo the challenging treatment.
After surgery to remove their tumors, breast cancer patients with a MammaPrint score recommending against chemotherapy had a 95% survival rate, said co-researcher Laura van’t Veer, the test’s inventor.
“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 clinical trial involved nearly 6,700 women at 111 medical centers in nine countries. It “represents what we in medicine call the highest level of evidence,” AACR President Dr. Jose Baselga said.
“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.
Previously, doctors guessed whether a woman needed chemo by measuring the tumor, examining its cells under a microscope, and using genetic testing to determine whether the tumor would respond to hormone therapy, Baselga said.
The MammaPrint test looks at a panel of 70 genes within the tumor itself to assess its aggressiveness and the odds it will come back without chemotherapy, van’t Veer said.
“Our test looks under the hood, at the engine of the tumor,” she said. “The biology tells more about the tumor than simply examining its size, because you’re really looking into the tumor.”
MammaPrint has been on the U.S. market since FDA approval in 2007. But, many cancer doctors have waited for the results of this clinical trial to see how well it works, Baselga said.
This study was presented at the American Association for Cancer Research (AACR) meeting in New Orleans one week after this release. There has been favorable editorial comment in medical journals following the meeting. It will be interesting to see if a majority of oncologists now “get on board” with this test. To date, MammaPrint has been much more popular in the rest of the world, then here in the U.S.
I think it’s a matter of public awareness, then the demand for the test that will drive physicians to routinely utilize this valuable test.
The Bottom Line:
If you have been diagnosed with breast cancer insist that a MammaPrint be performed to help you and your physician decide if chemotherapy is warranted. Chemotherapy is beyond “challenging treatment”. It dramatically reduces or destroys the quality of life.
Source: April 18, 2016 National Institutes of Health