New blood test detects pre-cancerous colorectal lesions with 81% accuracy

An experimental blood test has shown high sensitivity for detecting precancerous colorectal polyps, offering potential for cancer prevention. In a study involving over 1,500 adults in China, Japan, and Spain, the test identified 92% of stage I-III colorectal cancers and 81% of advanced adenomas, according to a report in The Lancet Gastroenterology & Hepatology. The test was also 85% accurate in ruling out precancerous lesions.

Researchers not involved in the study called the test a potentially valuable tool for preventing colorectal cancer. Because it distinguishes between low-risk and high-risk adenomas and cancers, the test could help prioritise patients for urgent colonoscopy. Doctors still recommend colonoscopy as the gold standard, with blood tests advised only for patients who cannot or will not undergo the procedure. Larger trials are needed, as the test was less effective at identifying flat, sessile lesions.