Dr. Lee on Tailoring Treatment to Tumor Sidedness in mCRC

Michael S. Lee, MD, assistant professor of medicine, Department of Molecular Therapeutics, UNC Lineberger Comprehensive Cancer Center, discusses tailoring treatment to tumor sidedness in patients with metastatic colorectal cancer (mCRC).

Primary tumor sidedness has emerged as a very important clinical feature utilized to drive treatment decisions. According to national consensus guidelines, patients with right-sided tumors, even if they are RAS wild-type, should not be treated with anti—EGFR therapy as part of their frontline regimen. If a biologic is given, the patient should receive chemotherapy with bevacizumab (Avastin), Lee says.

On the other hand, for patients with a left-sided tumor, recent data do support a survival benefit with adding an EGFR antibody like cetuximab (Erbitux) to the chemotherapy backbone. In the United States, it is reasonable to talk about starting with an alternative approach like bevacizumab and chemotherapy. Further, it is important to tailor treatment based on toxicity concerns and side effect profiles, says Lee.