Colorectal Screening：大肠癌筛查.ppt

Gobin is broken down in the small bowel so in theory there is no detection of gastric or ugi bleeding. Several studies (one RCT Zheng et al) Higher uptake (one test) around 60% More sensitive that gFOB (between 55% to 90% for cancer) Need to do more colonoscopies per 1000 screened pts (around 60, depends on preset threshold (6%)) Only one rct to support iFOB zheng found 32% reduction in rectal cancer mortality and 14% reduction in colon cancer mortalityblock rct of 94000 vs 97000 in control group age 30 years on 76000 participated ie 80% uptake If +ve then flexi sig if normal repeat iFOBT and if +ve then colo In addition there are a number of case-control studies and also pop based studies esp in from japan, holland and italy that show consistantly that the iFOB has better sensitivity than the gFOB for cancer but also in particular for advanced adenoma. The results vary but range from 55% to 90% for cancer and 30% to 55% for advanced adenoma Gives an approx positive predictive (ppp) for cancer Most trials of flexi sig screening look at one flexi sig aged 55 to 60 Biggest study to date is by Wendy Aitken in lancet 2011 14 sites (multicentre) age 55 to 64 one siggy only. Sent out questionaire first to all eligible to find out who would be interested ie 55% of those approached(total of 170432) and then randomised to control (113195) or flexi (57237) had 71% uptake ie 40674 screened ( this means only 39% of all eligible pts were screened) . Median follow up of 11 years 5% went on to have colonoscopy Note significant reduction in cr mortality of 31 % in intention to treat In the norwegian trials any polyp went onto have colo ie about 20% Probs with NORCCAP trial is that was small only about 13000 pts in screened group, Telemark even smaller ie only 400 4th study in process of being completed in Italy CORERO-1 trial 5000 invited and 32% uptake of whom 10% went on to have a colo so far have found similar pick up rate for cancer compared with iFOBT but higher