Aclinical trial involving more than 10,000 early-stage breast cancer patients found that women scoring low on a gene test for cancer recurrence can limit their post-surgery/radiation treatment to hormonal therapy without the need for chemotherapy. Five years after beginning treatment, these patients had less than a 1 percent risk of their cancer recurring at a distant site. The leader of the study was Joseph A. Sparano, M.D., a professor of medicine and of obstetrics & gynecology and women’s health at Einstein, and the results were published in September in the New England Journal of Medicine (NEJM).
The study illustrates how genetic information is transforming cancer care and could change the way breast cancer is currently treated: Guidelines now recommend erring on the side of caution and treating most early-stage breast cancer patients aggressively, using both hormonal therapy and chemotherapy together with surgery.
“The current treatment approach ensures that most women with high-risk cancers get treated, but it also means that most women with low-risk disease are overtreated and unnecessarily exposed to potentially toxic therapies,” says Dr. Sparano, also vice chair of medical oncology at the Montefiore Einstein Center for Cancer Care and associate director of clinical research at the Albert Einstein Cancer Center. “The compelling results of this study show that women with a low likelihood of cancer recurrence based on this test can effectively be treated without chemotherapy.”
The trial recruited the 10,253 eligible early-stage breast cancer patients at 900 sites worldwide. The women were representative of more than 100,000 of the 231,000 women diagnosed with breast cancer each year in the United States. They had invasive breast cancer, meaning cancer cells from inside milk ducts had penetrated nearby tissue but were still contained within the breast.
At the start of the trial, tumor tissue from each participant was tested using the Oncotype DX assay. This test analyzes the expression levels of 21 breast tumor genes and comes up with a “recurrence score” ranging from 1 to 100, with a low score associated with a low risk for recurrent cancer.
The findings published in the NEJM article involved a subset of 1,626 patients whose recurrence scores were between 0 and 10. They all were treated with hormonal therapy alone without chemotherapy.
After five years of treatment with just hormonal therapy (i.e., no chemotherapy following initial surgery/radiation), fewer than 1 percent of the women had experienced a recurrence of cancer beyond the breast, and only 1.3 percent had a recurrence of the cancer anywhere.
Future findings from the ongoing TAILORx trial will pertain to the larger group of participants with midrange cancer recurrence scores (from 11 to 25) on the Oncotype DX test.