Use of Biomarkers to Guide Treatment

The American Society of Clinical Oncology (ASCO) released new guidelines on using biomarkers to guide systemic therapy for women with metastatic breast cancer. ASCO’s Clinical Practice Guideline Committee approved the workgroup’s recommendations on July 20, 2015 and the complete guidelines may be found online at http://jco.ascopubs.org/content/early/2015/07/14/JCO.2015.61.1459.

The workgroup conducted a literature search and identified systematic reviews, meta-analyses, randomized controlled trials, prospective—retrospective studies, and prospective comparative observational studies published from 2006 through September 2014. They found 17 articles that met criteria for further review, and based the new guidelines on the findings of these studies. The guidelines recommend that in patients with metastasis that can be biopsied, biopsies should be performed to confirm disease.

Retesting of estrogen receptor, progesterone receptor, and HER2 status should be offered; however, evidence is lacking to determine whether changing treatment on the basis of change in receptor status affects clinical outcomes.

When there is discordance, the recommendation is to preferentially use the estrogen receptor, progesterone receptor, and HER2 status of the metastasis to direct therapy if supported by the clinical scenario and patient’s goals for care. Carcinoembryonic antigen, cancer antigen 15-3, and cancer antigen 27-29 may be used as adjunctive assessments, but not alone, when making metastatic breast cancer treatment decisions. The workgroup noted that re-biopsy and obtaining circulating tumor markers are recommendations based on the consensus of the workgroup members, and that studies to evaluate the clinical efficacy of tumor markers in women with metastatic disease are needed.