Although survival rates for early-stage breast cancer patients have improved over the last five years, many women still die from the disease. In this new study, the Georgetown team found that women whose tumors retain Stat5, a protein biomarker, have a highly favorable prognosis and may be cured by surgery and local therapy alone instead of additional regiments of chemotherapy or anti-estrogen therapy. Conversely, women whose tumors lost the Stat5 marker had a 7.6-fold increased risk of dying from recurrent breast cancer.
"Detection of the Stat5 marker in early stage breast cancer may lead to improved individualized therapy," said Hallgeir Rui, M.D., Ph.D., associate professor of oncology, Lombardi Comprehensive Cancer Center at Georgetown and principal investigator of the study. "This may include more careful follow-up and more aggressive treatment of patients at higher risk of breast cancer recurrence, and reduced treatment in patients with excellent prognosis."
Rui notes that the majority of promising breast cancer markers that have been identified over the last decade have failed to become useful in the clinical setting after follow-up studies. However, the design and results of this study give Rui and his colleagues room for optimism.
The study involved a retrospective analysis of two large, independent breast cancer patient materials that included over 1,100 patients, giving the study a solid statistical basis. Also, unlike some marker assays or tests, the assay for Stat5 is simple, inexpensive, and can be rapidly adapted to routine analysis in pathology laboratories using standard procedures.