Doctors want to find colon cancer before it spreads. A new look at blood tests called ctDNA shows they can detect advanced colon cancer fairly well. They found these tests catch about 72 percent of invasive cases. That means they miss roughly 28 percent of serious cancers. The blood test also correctly identifies people without cancer about 91 percent of the time. This is good news for avoiding false alarms.
However, the blood test struggles with early warning signs. It found only 13 percent of advanced precancerous lesions. These are growths that could become cancer if left untreated. The overall ability to spot these early problems was very low. The test missed most of them. This is a major gap in current screening options.
The study looked at data from 36,381 average-risk adults. These people had no symptoms and were not at high risk. The researchers compared the blood test results to colonoscopy findings. Colonoscopy remains the gold standard for finding these growths. The blood test cannot yet replace it for early detection.
Experts say more large studies are needed. We need to know if these tests work well enough for real-world use. They also need to know if the cost is worth it. Until then, colonoscopy remains the best way to catch these dangerous growths early.
