Biomarker could guide decision on follow-up breast cancer treatment

A group of investigators at Massachusetts General Hospital Cancer Center say they have identified a key equation on gene expression that should help identify which patients with estrogen-receptor-positive breast cancer will need follow-up treatment with an estrogen blocker after completing tamoxifen therapy.

Currently, these patients typically get a second round of Femara (letrozole). But the investigators say that examining dozens of tissue samples found that a high HOXB13/IL17BR ratio--where the expression level of HOXB13 is greater than that of IL17BR--could identify patients at a higher risk of seeing their tumors recur.

"Most patients with early-stage, ER-positive breast cancer remain cancer-free after five years of tamoxifen treatment, but they remain at risk of recurrence for 15 years or longer after their initial treatment," says Dr. Dennis Sgroi of the MGH Cancer Center and Department of Pathology, the lead author of the report. "Our biomarker identifies the subgroup of patients who continue to be at risk of recurrence after tamoxifen treatment and who will benefit from extended therapy with letrozole, which should allow many women to avoid unnecessary extended treatment."

They are not certain, though, adding that the results will need to be validated in a follow-up test before it can be rolled out to physicians as a new standard for treating breast cancer. But if it is validated, the knowledge would have a major impact on treatment protocols.

"This discovery means that about 60 percent of women with the most common kind of breast cancer can be spared unnecessary treatment with the concommitant side effects and costs," says Paul Gross, the director of the breast cancer research group. "But more importantly, the 40 percent of patients who are at risk of recurrence can now be identified as needing continued therapy with letrozole, and many will be spared death from breast cancer."

- here's the press release