Stool test for colorectal cancer screening--it's time to move!

Fecal occult blood testing (FOBT) is the most widely prescribed screening test for colorectal cancer (CRC) because it is simple, non-invasive, and it has been demonstrated that it reduces the mortality due to colorectal carcinomas (CRC). However, guaiac based fecal blood tests (gFOBT) suffer from poor sensitivity, particularly with respect to detecting early stages, as well as low acceptance among the population. Preliminary data on the detection of fecal proteins like calprotectin and tumour-M2-PK indicated that they might have better performance characteristics than the gFOBTs. However, these tests also suffer from low sensitivity and poor specificity especially for detecting early lesions. Recently developed immunological tests (iFOBT) demonstrate a significantly higher sensitivity and specificity. iFOBTs use antibodies specific to human hemoglobulin and therefore are not affected by the necessity of dietary and drug restrictions that otherwise limit the use of gFOBTs. At present iFOBTs seem to be the most cost-effective approach for non-invasive CRC screening. The analysis of fecal DNA represents an emerging new field for early detection of colorectal neoplasia. Small trials of multitarget assays demonstrated a sensitivity for CRC of 62 to 91% and a sensitivity for adenomas of 26 to 73%. The specificity of these assays is high ranging from 93 to 100%. The major drawback of fecal DNA testing, compared with other fecal colorectal cancer screening tests, is the unacceptable high cost.