Chemotherapy is the most dreaded part of breast cancer treatment for many women because of the horrid side effects. But what if you didn’t have to have this chemical cocktail to cure your cancer or keep it from coming back?
That was the focus of a study involving women with early-stage hormone-receptor-positive breast cancer, the type of cancer that uses the hormones estrogen and progesterone to grow and represents about half of all breast cancers. The goal was to see whether the guideline to give chemotherapy to almost all women with this form of breast cancer did indeed cut the risk of it coming back…or was unnecessary, at least for some.
Nearly 10,000 participants were given a genomic test called Oncotype DX. The test looks at 21 genes to create an estimate of how likely a woman’s breast cancer is to return and of how beneficial chemotherapy will be.
Some results of this test are cut and dried. A high “recurrence score” (26 and up) strongly suggests that chemotherapy would be beneficial, and a low score (0 to 10) strongly suggests that chemotherapy isn’t needed. But what about the majority of women, whose scores fall somewhere in the middle? They were the ones, 6,711 women in all, who the researchers zeroed in on.
These women had surgery to remove the cancer, either a mastectomy or breast conservation surgery plus radiation, followed by hormone therapy to block the cancer’s fuel source, but only half received chemotherapy as well. After nine years of follow-up, the researchers found that the two groups had similar outcomes: 83% of the women who hadn’t had chemo were still in remission…and so were 84% of the group that had had chemo.
The researchers concluded that overall, when you add back in women who score very low on the Oncotype DX test, the test could point to up to 85% of women with early hormone-receptor-positive breast cancer as being able to be spared chemotherapy without increasing their chances of a recurrence. Within that broad percentage of women, there are two key groups that emerged: Women over 50 years old with scores of 25 or lower on the test…and women 50 and under with scores of 15 or lower. (Treatment decisions tend to be more aggressive in younger women.)
WHAT THIS MEANS FOR YOU
If you have early-stage hormone-receptor-positive breast cancer, ask for the Oncotype DX test. Only about 60% of women eligible for the test actually get it, said Joseph A. Sparano, MD, the lead author of the study and professor of medicine and obstetrics, gynecology and women’s health at the Albert Einstein College of Medicine in New York.
If your genomic test score predicts a low or intermediate risk for the cancer to come back, talk to your doctor about whether skipping chemotherapy is a wise decision for you.
In the meantime, don’t skip other treatments for your cancer, including surgery and hormone therapy, a combination that has shown good results, and possibly radiation if breast-conserving surgery was performed, Dr. Sparano said.