First results for English bowel cancer screening revealed
MedWire News: Information on the first million patients participating in the Bowel Cancer Screening Programme (BCSP) in England suggests that uptake of guaiac fecal occult blood tests (gFOBt) and colonoscopy referrals is largely following predicted patterns.
"These early results indicate that the BCSP in England is on track to match the 16% reduction in [colorectal cancer] mortality found in the randomised trials of gFOBt screening," report Richard Logan (University of Nottingham, UK) and co-authors.
From 2006, men and women aged 60-69 years registered with the National Health Service in England were invited to complete three gFOBts at 2-year intervals, with full roll out planned by December 2009.
By October 2008, around 2.1 million individuals were invited for the first screening round, with overall uptake by 50% of men and 54% of women, in line with previous trial results.
Uptake was significantly lower in London residents compared with those in the four provincial regions (40 vs 55-60%), even after adjusting for socioeconomic factors.
Low uptake in London may be due to "problems with undelivered mail, the greater ethnic mix, large immigrant population and greater use of private healthcare in the London area," the team suggests.
Overall, 2.5% of men and 1.5% of women had an abnormal test, and 94% of these 21,106 participants attended a specialist screening practitioner. In all, 17,518 participants underwent further investigation for colorectal cancer mainly colonoscopy (98%).
Among these patients, cancer and higher risk adenoma were detected in 12% and 43% of men, respectively, and 8% and 29% of women. The majority (71%) of cancers were defined as early-stage disease (10% polyp cancer, 32% Dukes A, and 30% Dukes B).
Of note, 77% of cancers were left-sided (29% rectal, 45% sigmoid) and just 14% were right-sided. As predicted, women were more likely than men to have right-sided cancer (19 vs 12%) but less likely to have rectal cancer (20 vs 29%).
However, the overall prevalence of left- and right-sided cancers significantly differs from the expected rates calculated from UK cancer registry data of 67% and 24%, respectively, Logan et al observe.
The researchers suggest that the more aggressive right-sided tumors may be less amenable to screening than left-sided disease. "Another possibility is that right-sided cancers tend to produce detectable occult bleeding when they are larger than left-sided cancers," they say.
Logan et al conclude: "The intention is to replace the gFOBt with a faecal immunochemical test (FIT) in the next few years and based on the Dutch experience using a single FIT we might expect a 25% increase in uptake and up to a doubling of the cancer detection rate.
"However moving to a FIT will require a substantial increase in colonoscopy capacity," they note.
By Lynda Williams