A new study shows chemotherapy used to treat early stage breast cancer may not be effective.

The study took place over a 15-year period and looked at over 10,000 women in six countries.

Doctors found that patients in the intermediate risk range do not necessarily benefit from chemo.

They say alternative treatment methods would be for patients to solely undergo hormone therapy.

Doctor Joseph Sparano of Montefiore Medical Center says the study helps doctors properly suggest treatment.

"The bottom line is that we approach a patient now with this type of breast cancer, which accounts for about half of all breast cancers in the U.S., we can direct them to chemotherapy about 30 percent of the time and spare them the use of chemotherapy about 70 percent of the time," Sparano says. 

The findings are from the TAILORx trial.