Cleveland Clinic study explores colorectal cancer treatment options

Researchers at Cleveland Clinic have shared new findings about immune checkpoint inhibitors for treating colorectal cancer. The study involved nearly 19,000 patients who received these treatments in the U.S. It was led by Dr. Stephanie Schmit and published in JAMA Network Open. The study showed that immune checkpoint inhibitors significantly improved survival rates for patients with metastatic microsatellite instability-high (MSI-H) colorectal cancer. This aligns with previous clinical trials. The researchers also explored how some factors might enhance treatment effectiveness in patients with microsatellite stable (MSS) tumors, which are typically harder to treat. Immune checkpoints help prevent the immune system from attacking healthy cells. Immune checkpoint inhibitors work by removing this barrier, allowing the immune system to target cancer cells more effectively. Many colorectal tumors carry mutations that allow them to produce immune checkpoint proteins, helping them hide from the immune system. The FDA approved immune checkpoint inhibitors for MSI-H colorectal cancer in 2017, and they showed promising results in clinical trials. To see how these treatments worked in everyday medical practice, the research team analyzed health records from 2013 to 2019. The results confirmed that the inhibitors significantly improve survival in MSI-H patients. For MSS tumors, while most patients responded poorly, some did show lasting responses. Factors like enzyme levels and microbiome activity might influence the treatment's effectiveness, but more research is needed. Currently, doctors hesitate to prescribe these inhibitors for MSS tumors due to poor outcomes in clinical trials. However, these new findings may lead to new guidelines for treating these cases. The researchers aim to improve survival rates for MSS colorectal cancer patients who have had limited options until now.