“Understanding cancer heterogeneity could further reduce chemo use,” says cancer research expert Antonio Giordano, MD, PhD, Director of the Sbarro Institute for Cancer Research and Molecular Medicine at Temple University. “Further study of cases that can successfully be treated with hormone therapy and immunotherapy, and how to identify them, will unlock this potential.”

Giordano refers to the TAILORx study, published by the New England Journal of Medicine this week, which describes treatment outcomes in breast cancer, comparing cases receiving both endocrine therapy and chemotherapy, vs those receiving only endocrine therapy. Under certain conditions, including the early-stage development of tumor size, and the tumor not having spread to any peripheral lymph nodes, endocrine therapy alone resulted in nearly identical rates of survival and recurrence as endocrine- and chemotherapy combined.

“It is important to underscore that this specific study refers to patients with small tumors and no lymph node infiltrations,” says Giordano. “Women with early-stage breast cancer may be able to avoid chemotherapy, which is exciting, because there are pros and cons associated with it. The treatments have unavoidable effects on healthy cells as well as cancer cells.”

“The goal of precision medicine moving forward,” Giordano says, “is to identify more sophisticated approaches to this problem of cancer heterogeneity. Every type of cancer, at the molecular level, can have a cell environment that changes and evolves through the course of the disease. Or from patient to patient.”

“Only by understanding specific targets or molecules responsible for key cellular processes will we be able to understand, with precision, new options of therapeutic target that could replace chemotherapy altogether,” Giordano says.

“The precision target is not yet precise enough,” Giordano says. “But the option to spare many patients the potential harmful effects of chemo is a sign we are moving in the right direction.”