What to do after a positive FOBT
A man aged 52 years has a positive fecal occult blood test (FOBT) just two years out from a normal colonoscopy screening. He has no GI symptoms, does not take aspirin or nonsteroidal anti-inflammatory drugs, and has a normal blood count. Should this patient be referred back to gastroenterology? — Kim Horton, PA-C, Boston
There are a few issues to address here. First, why did this patient have a FOBT so soon after a normal colonoscopy? The use of FOBT within five years of a negative colonoscopy is discouraged (CA Cancer J Clin. 2006;56:143-159).
Second, the use of standard FOBT is no longer recommended, as the use of newer guaiac and fecal immunochemical testing are preferred because of their higher sensitivity. The recent guideline developed jointly by the American Cancer Society, the Multi-Society Task Force on Colorectal Cancer and the American College of Radiology explicitly recommends that screening be limited to tests that have single-application sensitivity for cancer >50%, thus excluding standard guaiac tests as an acceptable option (Gastroenterology. 2008;134:1570-1595; Am J Gastroenterol. 2009;104:739-750).
Finally, any positive FOBT needs to be followed up with a colonoscopy. Refer the patient back to gastroenterology. — Sharon Dudley-Brown, PhD, FNP-BC, co-director, gastroenterology & hepatology, nurse practitioner fellowship program, Johns Hopkins University Schools of Medicine & Nursing, Baltimore (154-09)