Specific Aims: 1) To determine the effect of FOBT screening on colorectal cancer mortality, non-colorectal cancer and all-cause mortality by age (by 5 year age groups) and gender in the three fecal occult blood testing trials updated to 30 years of follow-up 2) To determine the overall effect of fecal occult blood testing (FOBT) screening on colorectal cancer mortality, non-colorectal cancer and all-cause mortality in the three fecal occult blood testing trials updated to 30 years of follow-up Background: Current guidelines for colorectal cancer screening recommend starting screening at age 50 for average-risk individuals with fecal occult blood testing (FOBT) or fecal immunochemical testing (FIT), FOBT/FIT+ flexible sigmoidoscopy, or colonoscopy, without specifying an age at which to stop offering screening. There have been three randomized controlled trials of screening using FOBT that showed a reduction in colorectal cancer mortality. Updating results from the FOBT trial in the US, we have recently reported that screening may not reduce all-cause mortality, and that benefit of screening may differ for men and women of different ages. In our study, women <60 did not benefit from screening for colorectal cancer. However, we were limited in our analyses by small size of the groups and low event rates. To improve our understanding of these findings, and inform guidelines, the effect of screening on colorectal cancer mortality and all cause mortality in various age and gender groups need to be examined in a larger sample. Project Design and methods: This project involves updating the vital status and cause of death of all participants from UK and Danish fecal occult blood testing trials and pool the data with the Minnesota Colon Cancer Control Study up to 30 years of follow-up and calculating CRC, non-CRC and all-cause mortality estimates. We plan to compare colorectal cancer (CRC) mortality and non-colorectal cancer mortality rates between the screened and unscreened groups, by age categories at time of randomization of 5 year (50-54, 55-59, 60-64, 65-69, 70-74, 75-80) and 10 year (50-59, 60-69, 70-80) intervals. We will also stratify the above analyses by gender subgroups.
We aim to determine the long term effect of screening on colorectal cancer, non-colorectal cancer and all- cause mortality in age and gender sub-groups by updating and combining data from all three randomized controlled clinical trials comparing FOBT to no screening. VA has put much effort into studying and implementing colorectal cancer screening. Colorectal cancer incidence increases with age. It is one of the most common cancers among the veteran population. An estimated 75% of VA patients are over age 50, and 40% are over age 70. Also, women constitute 10% of veteran patients, and the number is expected is increase. Recent work showed that between 1998 and 2003, 2,402,657 veterans underwent CRC screening, with FOBT being the predominant method and increasing over time. A better understanding of the ideal target population to be screened would build on VA leadership in research in this area and help focus efforts at resource- effective implementation.
