Two Step FOBT for Colon Cancer Launched
Research published by a Scottish team indicates that a two step screening process of fecal occult blood can identify those patients who are more likely to develop colorectal cancer. The findings were published in the medical journal Gut.
Guaiac fecal occult blood testing (gFOBT) is used to screen for colon cancer, but there are limitations with this screening approach. Newer testing methods employ fecal immunochemical testing (FIT), but these approaches can be expensive.
The team evaluated a two-tier approach in patients with positive findings from gFOBT followed by FIT prior to colonoscopy. Findings were compared to those obtained with colonoscopy. Specifically, the team evaluated a new simplified FIT card collection.
Over 1,100 patients who had positive findings from gFBOT were asked to provide specimens for analysis. Of those, 558 individuals returned samples to the researchers. FIT testing was positive in 256 patients and 302 were negative.
Among the FIT-negative patients, two patients had colorectal cancer and 12 had adenomatous polyps. 93 of those patients had a normal colonoscopy examination. Among the cohort with positive results from FIT testing, 47 had cancer and 54 had high risk polyps. Only 34 of the 256 FIT-positive patients had normal colonoscopy with no pathology.
The sensitivity for cancer with this tiered approach was 95.9 percent, specificity was 59.2 percent. The positive likelihood ratio was 2.35 and the negative likelihood ratio was 0.07. For cancer and high-risk polyps combined, sensitivity was 87.8 percent, specificity was 65.3 percent, positive likelihood ratio 2.53 and negative likelihood ratio was 0.19.
The team advocates for testing patients with FIT who are positive on gFOBT screening. This screening approach is effective in identifying patients with a higher risk of developing colorectal cancer and adenomatous polyps. Notably, this screening method was adopted by the Scottish Bowel Screening Programme.
The preferred method for screening cancer, according to most colorectal surgeons, is colonoscopy. However, this approach has limitations in that patients are often uninterested in undergoing the test and is not always covered for patients who are underinsured. In addition, colonoscopy is associated with some complications, such as perforation during the procedure. Other complications may arise secondary to use of anaesthesia and sedatives during testing.
November 2, 2007 Related topics: New Technology & Innovation, Diagnostic, Surgery, Gastroenterology