The type of hormone therapy administered was dependent upon whether women were premenopausal or postmenopausal-91% of postmenopausal women received an aromatase inhibitor-based regimen, whereas premenopausal women were most commonly prescribed either an endocrine therapy regimen comprising either tamoxifen alone or tamoxifen followed by an aromatase inhibitor (78%).
The findings could be a game-changer in breast cancer care, researchers and experts said.
Dr. Joseph Sparano of Montefiore Medical Center in NY, lead author of the study says that the impact of this test could spare thousands of women from chemotherapy and for them surgery and hormone therapy could be sufficient.
The New England Journal of Medicine published a study on Sunday that examined a popular genetic test that estimated cancer risk based on nearly two dozen genes linked with the recurrence of breast cancer, according to CNN.
One more thing the new findings show? "I've been anxious for a long time about unnecessary treatment for cancer, and unnecessary side effects from chemotherapy".
The doctors who treated the woman say while their approach is still experimental, they believe it could be adapted to treat other kinds of cancer as well.
"There will still be some women that need chemotherapy".
Women were deemed to have a medium level risk of the cancer coming back based on a 21-gene panel known as Oncotype DX from Genomic Health.More news: Serena withdraws ahead of Sharapova clash
The study used a gene test done on tumors to help decide whether a woman would benefit from chemo or if they could receive hormone therapy. Of the 10,273 women tested, 6,711 (69%) had a score of 11-25. "The trial was created to address this question, and provides a very definitive answer".
The extensive study revealed that approximately 70 percent of women diagnosed with early-stage breast cancer might not benefit from a treatment protocol that includes chemotherapy.
"Patients really struggle having to make that decision, and now they don't have to. But the results came out either low risk, high risk or intermediate risk", Abraham added.
Cancer is complex and challenging to study, and news reporting on the disease easily lends itself to hype, contradiction and misinterpretation.
However, among younger women with scores 16 to 25, outcomes were slightly better in the chemotherapy group, so in those cases, doctors may urge patients to consider a chemo regimen.
Those with a recurrence score of up to 10 out of 100 have been shown not to benefit from chemo and those with a score of 26 or higher do benefit.
Those women should carefully discuss their options with their oncologist, said Brawley, because they would likely be candidates for the more aggressive, dual therapies. "I may have had chemotherapy possibly unnecessarily but I helped someone else in the future", said Dr. Butler.
Another study at the conference found that Merck's immunotherapy drug Keytruda worked better than chemo as initial treatment for most people with the most common type of lung cancer, and with far fewer side effects.
"Side effects, such as hair loss, severe pain and infertility, can be utterly devastating and linger long after they walk out the hospital doors".