Washington: Researchers have found that the breast cancer index (BCI) can accurately identify patients who continue to be at risk after five years of treatment with either tamoxifen or the aromatase inhibitor anastrozole.
The study's co-author Paul Goss, MD, PhD, director of the Breast Cancer Research Program at Massachusetts General Hospital (MGH) Cancer Center, said that they have validated a unique 'fingerprint' in the primary tumour of breast cancer patients that can help identify a high or low risk of cancer recurrence.
He said that this may help offer prolonged treatment to patients who remain at risk and, importantly, to avoid the costs and side effects of treatment in those at low risk.
Standard treatment for early-stage, ER-positive breast cancer includes five years of treatment with either tamoxifen or an aromatase inhibitor, drugs that block the action of estrogen.
MGH researchers previously developed, in collaboration with investigators from bioTheranostics, Inc., two biomarkers for recurrence risk assessment - the molecular grade index, which measures expression levels of five genes related to tumor proliferation; and the H and I ratio, which compares expression levels of two other genes. BCI is a combination of both biomarker s and has been shown to identify patients who are at risk of early recurrence despite receiving hormonal treatment.
The current study, led by Dennis Sgroi, MD, of the MGH Cancer Center and Department of Pathology, was designed to compare the ability of the BCI to predict long-term recurrence risk with that of two other gene-expression signatures that can predict risk in the first five years.
It was found that the BCI was able to clearly distinguish 60 percent of patients whose risk was quite low from 40 percent who continued to be at significant long-term risk.
The study is published in Lancet Oncology.