CHARLOTTE, NC (WBTV/AP) - Most women with the most common form of early-stage breast cancer can safely skip chemotherapy without hurting their chances of beating the disease, doctors are reporting from a landmark study that used genetic testing to gauge each patient's risk.
The study is the largest ever done on breast cancer treatment, and the results are expected to spare up to 70,000 patients a year in the United States - and many more elsewhere - the ordeal and expense of these drugs.
"This will change my practice dramatically," said Dr. Antionette Tan, the Chief of Breast Medical Oncology at Levine Cancer Institute.
The breast cancer study focused on cases where chemo's value increasingly is in doubt: women with early-stage disease that has not spread to lymph nodes is hormone-positive (meaning its growth is fueled by estrogen or progesterone), and is not the type that the drug Herceptin targets.
The study gave 10,273 patients a test called Oncotype DX, which uses a biopsy sample to measure the activity of genes involved in cell growth and response to hormone therapy, to estimate the risk that a cancer will recur.
About 17 percent of women had high-risk scores and were advised to have chemo. The 16 percent with low-risk scores now know they can skip chemo, based on earlier results from this study.
"It came back with a low score. Chemo would have been no benefit to me," said Neel Stallings a two-time cancer survivor.
The new results are on the 67 percent of women at intermediate risk. All had surgery and hormone therapy, and half also got chemo.
After nine years, 94 percent of both groups were still alive, and about 84 percent were alive without signs of cancer, so adding chemo made no difference.
"Now we are able to do more tailoring of our treatment recommendation and identify women who do not need chemotherapy," said Doctor Tan. "Now, with the results of this trial, we have prospective, definite results to guide our patients."
"The impact this can have on literally thousands and thousands of women is huge," said Michelle Adams who is on the Board of Directors for Susan G. Komen in Charlotte and also a cancer survivor.
Adams was a part of this study and was found to have intermediate risks. She underwent chemotherapy.
"You hear about the side effects but until you go through them, you don't understand how rough they can be," said Adams. "It is difficult, it is definitely difficult, so you don't want to do it unless you really need to."
Adams said at the time she was diagnosed at age 36, she said chemotherapy was a safety blanket, but after this study, her thoughts have changed.
"At the time, I really wanted to go through Chemo. Now, knowing what it entails, my answer might be different," said Adams.
Adams says Susan G. Komen helped fund the study and they are pleased with the results.
Certain women 50 or younger did benefit from chemo; slightly fewer cases of cancer spreading far beyond the breast occurred among some of them given chemo, depending on their risk scores on the gene test.