9Colon cancer and the elderly: From screening to treatment in management of GI disease in the elderly
Section snippets
Screening and surveillance methods
Preventive methods to reduce the incidence and mortality from colorectal cancer distinguishes screening from surveillance. Screening includes testing of asymptomatic individuals at average risk for colorectal cancer or at higher risk because of a family history to diagnose colorectal cancer or precancerous neoplastic adenomas. Surveillance involves monitoring of individuals with premalignant conditions including inflammatory bowel disease, primary sclerosing cholangitis or with previous
Fecal immunochemical testing
Immunochemical testing (FIT) for human globin or haemoglobin is more specific, particularly for lower gastrointestinal bleeding and requires simpler collection methods than qFOBT tests and has become the preferred fecal test in Europe and Japan. Several FIT are available whose sensitivity for detection of cancer and advanced adenomas depend upon the haemoglobin threshold used. Side to side testing of differing FIT's against standard gFOBT methods have regularly shown superiority for the FIT's
Stool DNA testing
Since colorectal cancer and precancerous adenomas often contain altered DNA which is shed into the gastrointestinal lumen and DNA is stable in the stool, fecal tests seeking altered DNA are being evaluated. Multiple DNA markers need to be tested usually including point mutations in K-ras, APC, P53, BAT26 (a probe for micro-satellite instability), methylated promoter markers and several DNA integrity tests. One disadvantage of DNA testing is that at least 30 gms of stool need to be collected and
Chemoprevention for reducing the risk of colorectal cancer risk
Presently, the sole accepted method of risk reduction (prevention) of colorectal cancer is detection and removal of preneoplastic adenomas. This represents secondary prevention – the elimination of existing lesions that may progress to cancer. Primary prevention focuses upon risk reduction of the carcinogenic process from a normal colorectal mucosa to benign adenomatous neoplasia. Risk reduction methods have included lifestyle changes, including increasing physical activity, dietary factors and
Summary
Colorectal cancer in the elderly is common, shows differing clinical and biologic features and can be detected and prevented using several screening strategies. Because progression of adenomas to cancer takes a decade, invasive screening colonoscopy has risks and comorbidities reduce life span in the elderly, screening should be modified after age 75 and avoided after 85. However, nutritional measures may have a place in prevention.
Treatment algorithms for all stages of colorectal cancer,
Acknowledgements
Supported in part by NCI grant U54CA100926; UL1RR024143 from the NCRR and the NIH Roadmap for Medical Research.
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