Gene test can help some breast cancer patients avoid chemo

Gene test can help some breast cancer patients avoid chemo

A large percentage of women with early-stage breast cancer who have been identified as having a high risk of recurrence should consider forgoing chemotherapy based on the biological makeup of their tumor, according to research published Wednesday.

Nearly half of early breast cancer cases that meet traditional criteria for high risk can be treated just as effectively without chemotherapy as with it, according to the study, which used genetic testing to analyze tumors.

The findings, published in the New England Journal of Medicine, are among the strongest to demonstrate how personalized medicine — applying treatments based on the genetic makeup of individuals or their disease — can be used to refine cancer therapies and, in this particular case, avoid overtreating individuals, doctors said.

Many breast cancer patients are overtreated by chemotherapy.

The new report is a landmark study that should have immediate implications for breast cancer care, said Dr. Laura Esserman, director of UCSF’s Carol Franc Buck Breast Care Center, who works with van ‘t Veer but was not part of the MammaPrint research.

The risk of recurrence for each woman was determined two ways: by the MammaPrint test and by a more traditional clinical test that looks at the patient’s age, whether she’s gone through menopause and the size of the tumor, among other things.

The study found that for the 1,550 women who were identified as high risk by traditional tests but low risk by genetic testing, the chance of recurrence — about 5 percent after five years — was almost identical whether they received chemotherapy or not.

In the United States, about 230,000 women are diagnosed with breast cancer every year, the majority of them with early-stage cancer, meaning it’s located only in the breast and, in some cases, the lymph nodes.

Karuna Jaggar, executive director of the patient advocacy group Breast Cancer Action, said she welcomed any strong research that allows women to make informed decisions about their own care.