The American Society of Clinical Oncology (ASCO) announced the release of new clinical practice guidelines on the use of biomarker assays. The guidelines intend to aid clinicians in deciding on adjuvant systemic therapy for women with early stage invasive breast cancer and known hormone receptor and HER-2 status.
“In the era of precision medicine, the role of biomarkers in guiding clinical care is greater than in the past. An extensive number of new tests have come out in the last 5 to 10 years, but not all have sufficient evidence of clinical utility,” Lyndsay N. Harris, professor of medicine and co-chair of the ASCO expert panel that developed the guideline, stated in a press release.
The guidelines recommending proper use of biomarker assays are based on an extensive literature review of studies published between 2006 and 2014. These encompass systematic reviews, meta-analyses, randomized controlled trials, prospective-retrospective studies, and observational studies. Harris and colleagues also included studies reporting data on overall survival, relapse-free survival, and disease-free survival. They identified 50 breast cancer studies, of which 19 evaluated the feasibility of using biomarker assays for determining adjuvant (post-operative) systemic therapy.
Based on this data, the ASCO panel recommend the use of Oncotype DX (Genomic Health), EndoPredict (Sividon Diagnostics), PAM50 (Prosigna, NanoString Technologies), Breast Cancer Index (Bio Theranostics), and the urokinase plasminogen activator and plasminogen activator inhibitor type 1 assay for guiding clinicians on such therapy decisions.
Since none of the included studies evaluated choice of an assay in relation to specific treatments or regimens, the panel judged that no biomarker test should be used to guide decisions on specific drugs or treatment regimens. The exceptions are tests for estrogen and progesterone receptors as well as HER2 status. The expert panel also underscored that treatment decisions need to take several factors, such as disease stage, specific comorbidities, and patient preferences, into account.
The guideline is issued in spite of the lack of prospective trials confirming the utility of these assays and a lack of data on reproducibility of assays. The panel acknowledged these limitations of their recommendations, and stated that more research is necessary to refine and redefine the clinical value of these biomarkers.
“These latest recommendations truly inform physicians about which tests need to be performed,” Dr. Harris said. “But this is not all that goes into patient care. Doctors need to continue discussions with patients to develop individualized treatment plans.”