Blood test may outshine scans for colorectal cancer tracking

This study is looking at whether a blood test that detects tiny bits of tumor DNA (called ctDNA) can help doctors more accurately assess how well treatment is working and predict if cancer will come back in people with advanced colorectal cancer. About 497 participants who are receiving radiation and chemotherapy, with or without an immunotherapy drug, will have their ctDNA levels monitored alongside standard CT scans. The goal is to see if the blood test can detect cancer changes earlier than imaging, potentially leading to faster treatment adjustments.