Dr. Isakoff pointed out, however, that the population in the study is from a registry of patients eligible for the 21-gene assay, which can only be used for patients with ER-positive and HER2-negative tumors.
“In other words, this is not a random sample. This is a sample of patients for whom the treating physician was on the fence about chemotherapy and in some way thought that getting an oncotype might be helpful,” he said.
He added that although the study findings “don’t change anything we have been doing, they provide reassurance that oncotype is a reasonable test to consider in patients with male breast cancer for whom we’re considering including or avoiding chemotherapy,” he said.
A funding source for the study was not reported. Dr. Massarweh disclosed stock or ownership in Radius Health, consulting for Novartis, and institutional research funding from multiple companies. Three coauthors are employees and stockholders of Genomic Health, maker of the Oncotype DX assay used in the study. Dr. Isakoff reported no conflicts of interest related to the study
SOURCE: Massarweh SA et al. 2018 Mar 27. doi: 10.1200/JCO.2017.76.8861.