Test Predicts Which Breast Cancer Patients Can Avoid Chemo
A new genetic test developed at Montefiore Medical Center in New York has been successful in predicting which early breast cancer patients would not need chemotherapy.
By searching for the presence of 21 genes related to breast cancer, the test is able to produce a score that reflects the likelihood of breast cancer recurrence. On a scale of 0-100, the higher the score, the higher the chance the disease will return again.
The team at Montefiore tested the effectiveness of the test on 10,273 women with early-stage, hormone-receptor positive breast cancer, all between the ages of 18-75. The type of cancer studied is driven by estrogen and progesterone hormones, and accounts for 2 out of 3 breast cancer cases in the U.S.
The test, called the Oncotype DX test, predicted that 16 percent of the patients were at low risk for recurrence (score of 10 or less), 67 were at an intermediate risk (score of 11-25), and 17 percent were at a high risk (score of 26 or higher). Women at high risk were then treated with a combination of chemo and hormone therapy, while women with low risk were treated just with hormone therapy. Those with intermediate risk were given either just hormone therapy, or a combination therapy.
Furthermore, 99 percent of the low-risk patients did not experience recurrence after five years, showing the accuracy of the test. Patient disease-free survival rate after that time was also high, at 94 percent, paired with a low risk of return cancer, at less than 1 percent. in patients.
Typically, women who develop hormone-positive breast cancer receive chemotherapy to kill off cancer cells that may have spread in order to reduce the chance of recurrence. However, sometimes this therapy is unnecessary, but this test could enable doctors to determine which women shouldn't undergo chemotherapy.
Results were published in the New England Journal of Medicine.