Many women with early-stage breast cancer may be able to forgo chemotherapy, according to a recent study published in The New England Journal of Medicine. The findings could affect 60,000 women in the United States.

Many women with breast cancer undergo a genetic test that analyzes the tumor and looks for the presence of 21 genes associated with a high chance of recurrence. The genetic testing results in a score of 0 to 100. Women who score 0 to 11 can skip chemo, and women who score over 26 are advised to undergo the treatment. The study aimed to determine whether doctors should offer chemotherapy to women whose scores fell in the middle range, or 11 to 25.

To conduct the study, scientists followed 10,273 women who had the most common type of breast cancer — known as the estrogen-receptor positive, HER-2 negative form — that had not spread to lymph nodes. Seventy percent of these women had gene test scores of 11 to 25.

Patients were randomly assigned to receive chemotherapy and hormonal therapy or only hormonal therapy. The researchers examined the two groups to see how many patients remained cancer-free or had cancer recur, whether in the same location of the body or elsewhere. They also assessed overall survival.

The study found that there was no significant difference between the two groups. The findings suggest that doctors can safely tell women who fall into the middle range of genetic test scores to skip chemotherapy. Researchers say this will prevent overtreatment. Avoiding chemotherapy can improve a women’s quality of health, as the treatment often has harsh side effects, including nausea, vomiting and hair loss.