New research finds a genetic test can predict, for some patients, whether breast cancer will return after treatment.

Researchers tested key genes in tumor samples from more than 400 patients with estrogen-dependent breast cancer that hadn’t spread to the lymph nodes.

Based on the test, the patients were ranked as either low, intermediate or high risk for recurrence.

The women were followed for 10 years and researchers found their predictions were accurate. Women ranked as low risk had a 6 percent recurrence rate after 10 years, intermediate patients had a 7 percent rate of recurrence and high risk women had a 30 percent recurrence rate.

Experts said the findings represent evidence that breast cancer treatment is moving toward individualized care.

“We can provide personalized advice to patients as opposed to talking about what happens to large groups of women,” said Dr. Melody Cobleigh, an oncologist and researcher at Rush University Medical Center in Chicago.

Researchers also found the test helped identify patients for whom chemotherapy was most beneficial, and those for whom the side effects may outweigh any benefit.

“The test told me that it would be less than 1 percent, that the chemo would really help me. So, I was very glad to hear that and I decided not to do chemotherapy,” said Susan LaPorta, a breast cancer patient.

About a quarter of the women in the study were classified as high-risk for recurrence. These women had the most benefit from chemo. Low-risk women made up about half of the patients; these women had minimal chemo benefits.

The federal Food and Drug Administration approved the test in February. As many as 50,000 women a year are diagnosed with estrogen-positive node-negative breast cancer.

The study is published in the New England Journal of Medicine and was presented Friday at the San Antonio Breast Cancer Symposium.