Colonoscopy Free?

Apparently, not yet. However, promising results from a study in the New England Journal of Medicine capitalize on our understanding of the genetic basis behind colon cancer. Colon cancer arises when four or five genes become mutated. In more than 90% of cases, it is mutations in the adenomatous polyposis coli (APC) gene that initiate colorectal tumours. The researchers investigated whether it was possible to detect APC mutations in fecal DNA using a new developed method known as digital protein truncation, a technique that could identify mutations in a sensitive and specific manner. Stool samples were collected from 28 patients with nonmetastatic colorectal cancers, 18 patients with adenomas that were at least 1 cm in diameter and 28 control patients. The test managed to identify mutations in 26 of the 46 patients with neoplasia (57%), and in none of the control patients.

Although successful in preventing false positives, which is a common occurrence with the current method of checking the stool for blood, the fact that the method only identified cancers in 50% of the patients suggests that this is only the first step in a long process. However, the researchers did overcome the somewhat unenviable task of sorting through the stool samples and managed to identify APC genes in each of the 74 stool samples.

Further research is underway, and the group predicts that an accurate and practical version of the test may be available within the next five years.


  1. Traverso GT, Shuber A, Levin B et al. Detection of APC mutations in fecal DNA from patients with colorectal tumours. NEMJ 2002;346:311-320.