Dr. Atreya on Questions Remaining With Tumor Sidedness in CRC

Chloe E. Atreya, MD, PhD, assistant clinical professor, Department of Medicine, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, discusses questions regarding sidedness in colorectal cancer (CRC).

Tumor sidedness is established as an independent prognostic factor that Atreya says will impact how patients with CRC are treated. Although there are known differences in the microbiome of the right and left side of the colon, the reason behind that is not yet understood. Atreya says that the microbiome is playing an increasingly important role in CRC research. According to the NCCN guidelines, EGFR-targeted antibodies are an option for patients who have left-sided RAS wild-type tumors, but are not recommended for use in those with RAS-mutated or right-sided tumors in the first-line setting.

There is also research investigating the potential with cancer stem cells on the right and left side of the colon. Each side has different embryologic origins, and that may impact potential treatment, Atreya explains.