More women diagnosed with early-stage breast cancer may be able to forego chemotherapy without risking their chances for survival, according to a study published in the New England Journal of Medicine.
The study used genetic testing to determine women’s Oncotype DX score, which calculates the likelihood of cancer recurrence on a scale of one to 100. Higher scores mean a higher likelihood the cancer returns.
Most practitioners — including Emily Albright, MD, an MU Health Care surgical oncologist — have already been using the Oncotype DX score as a guide for therapy. For patients identified in the low-risk group with a score of 10 or lower, chemotherapy is not recommended because with anti-estrogen hormone treatment alone the overall survival was 98 percent at five years. Patients identified as high risk with a score of 26 or more have been shown to benefit from chemotherapy.
Until the release of the new study, though, there was a scientific gap in how to treat women who scored in the intermediate range with a score of 11 to 25.
“We used to tell patients, ‘You may benefit, or you may not,’ ” Albright said. “But these new results look specifically at those patients at that intermediate risk.”
The study demonstrates that women who land in the intermediate range can forego chemotherapy without compromising survival. The subgroup that may continue to benefit from chemotherapy are women under 50 years old with recurrence scores from 16 to 25.
“Now we can have a better-informed discussion with patients explaining that they’re unlikely to benefit from chemotherapy,” Albright said.
The new findings could spare up to 70,000 American women per year diagnosed with early-stage breast cancer from the chemotherapy side effects.
Most people are aware of the short-term chemotherapy side effects, such as nausea, hair loss and fatigue, but there also can be long-term complications, including neuropathy and heart dysfunction.
Estrogen-receptor-positive and progesterone-receptor-positive breast cancers are stimulated to grow by those hormones. Anti-estrogen therapy serves to block this mechanism. The women who qualify for the anti-estrogen therapy typically take an oral medication for about five to 10 years. While there are side effects such as hot flashes and mood swings, they are not as destructive as chemotherapy.
Albright said the medical community has been waiting for this study’s results for some time.
The TAILORx (Trial Assigning Individualized Options for Treatment) trial used a 21-gene assay called Oncotype DX to calculate the likelihood for recurrence in nearly 10,000 women with hormone-receptor-positive, HER2 negative, axillary node negative breast cancer. In addition to the information about the role of chemotherapy in this group, “We should also take away from the results is that the survival rate from breast cancer is quite good,” Albright said.
Patients in the intermediate risk category who have had nine years of follow-up care have about an 84 percent disease-free survival rate, regardless of whether they were treated with chemotherapy or anti-estrogen therapy alone.
“I was very excited to hear these results,” Albright said. “I think this will allow more women to get through their cancer treatment faster, with the same good outcome, and back to their lives sooner.”