Chemotherapy is an unnecessary and possibly dangerous treatment for many women being treated for early stage breast cancer, according to a study released by New York's Montefiore Medical Center.
The study, which investigated the value of gene-activity test Oncotype DX to gauge individual patient’s risk, says many women with early-stage breast cancer could skip the usually prescribed chemotherapy treatment without lowering their odds of beating the disease.
Study leader Dr. Joseph Sparano says the test identified a group of women whose cancers were so likely to respond to hormone blocking drugs that adding chemotherapy to their treatment would be of little, if any, benefit. Chemotherapy treatments would unnecessarily expose them to other health risks and side effects.
Independent observers including New York’s Memorial Sloan Kettering Cancer Center's Dr Clifford Hudis agree.
The usual treatment for breast cancer is surgery which is followed by taking hormone-blocking drugs, often for many years. However, many patients were also encouraged to have chemotherapy in an endeavor to destroy any stray cancer cells that may have spread from the breast and could set in elsewhere. Doctors have known for some time that most women who have had surgery and are on a prescribed hormone blocking treatment don’t need chemotherapy, but up until now there had been no way to safely identify who.
Dr. Sparano said study participants who skipped chemotherapy had less than a one percent chance of cancer recurring elsewhere within the next five years.
Studies in the past have looked at how women classified as high, intermediate and low risk by the test have fared, but the new study also assigned treatment based on risk scores, and tracked recurrence rates.
Although full study results have not yet been released, independent monitors strongly recommended results of the low-risk group to be released, because it was clear that adding chemotherapy would not improve their success rate, and could in fact add other health risks.
Of the low risk group in the study, 99 percent had no breast cancer relapse after five years, 98 percent were still alive and 94 percent were totally invasive cancer free, including new cancers at other sites or in the opposite breast.
University of California breast cancer specialist Dr. Hope Rugo says “These patients who had low risk scores by Oncotype did extraordinarily well at five years. There is no chance that for these patients, that chemotherapy would have any benefit.”
Breast cancer survivor and advocate Mary Lou Smith, who helped design the trial said she thinks women “would be thrilled” to skip chemotherapy.
“Patients love the idea of a test to help reduce uncertainty about treatment”, she said. “I’ve had chemotherapy. It’s not pretty.”
The test used in the study costs $4,175, and is covered by many insurers and Medicare. Dr. Hudis said he hoped the new study results should encourage other manufacturers to compete on both price and accuracy.
“The future is bright for gene tests to more precisely guide treatment," said Hudis.