Secondary prevention: screening and surveillance of persons at average and high risk for colorectal cancer

Operative colonoscopy in cancer patients

Gastrointestinal endoscopy has experienced tremendous developments in technology and equipment over the past decades. It is not only a diagnostic tool, but it also allows some interventional treatments in benign and malignant digestive diseases. Operative colonoscopy has been used to perform curative treatment of various kinds of polyps, flat and carpet-like adenomas and early colorectal carcinomas. Endoscopic palliative treatment strategies, such as the placement of self-expandable metal stents (SEMS), laser ablation, photodynamic therapy (PDT), argon plasma coagulation (APC), electrocoagulation, and injection therapy, have been proved to effectively alleviate advanced colorectal cancer (CRC) associated symptoms and maintain or improve the quality of the patient's remaining life.

Colorectal cancer prevention

Colorectal cancer is the second leading cause of mortality in the United States. In the United States, the cumulative lifetime risk of developing colorectal cancer for both men and women is 6%. Despite advances in the management of this disease, the 5-year survival rate in the United States in only 62%. Because only 38% of patients are diagnosed when the cancers are localized to the bowel wall, it is likely that widespread implementation of screening could significantly improve the outcome. Colorectal cancer screening is cost effective, irrespective of the methods used. In addition to currently available methods (fecal occult blood, flexible sigmoidoscopy, colonoscopy, and double contrast barium enema), computed tomographic colonography (virtual colonoscopy) and stool-based molecular screening are under development. Four classes of chemopreventive compounds have demonstrated efficacy in reducing recurrent colorectal adenomas and/or cancer in randomized, controlled trials. They are selenium, calcium carbonate, hormone replacement therapy, and nonsteroidal anti-inflammatory drugs. The mechanisms of action of nonsteroidal anti-inflammatory drugs include inhibition of the cyclooxygenase system as well as cyclooxygenase-independent effects. Considerable effort is being expended to define chemopreventive activity, optimal dose, administration schedule, and toxicity for the coxibs in adenoma recurrence prevention trials. The threshold for tolerating toxicities is very low in asymptomatic individuals at minimally increased risk for colorectal neoplasia.

Do Gastroenterologists Notify Polyp Patients that Family Members Should Have Screening?

OBJECTIVE

The objective of this study was to determine whether patients found to have adenomatous polyps or cancer were notified that their relatives should have screening, due to an increased risk of developing colorectal cancer.

METHODS

Consecutive (n = 121) colonoscopy patients from December of 1999 to October of 2001 found to have adenomatous colon polyps or colon cancer formed the study group. Charts were reviewed for documentation of relative notification, and when documentation was not present, study subjects were contacted by telephone.

RESULTS

Overall, 71% had data that were able to be evaluated; the remaining 29% were unable to be contacted because of changes of address or phone numbers. Adenomatous polyps were seen in 95%, and cancer seen in 5%. Overall, 30% of the patients were notified: 23 of 82 (28%) in the polyp group and 3 of 4 (75%) in the cancer group. Advanced adenomas or multiple adenomas were noted in 28 of the 82 (34%). Of those, 8 of 28 (29%) were notified.

CONCLUSIONS

Gastroenterologists should be aware of the need for increased attention to family notification, especially in those with advanced adenomas or multiple adenomas. Template notification letters may complement the polyp surveillance programs that many colonoscopists use.

Colorectal cancer chemoprevention--an overview of the science

The development and dissemination of sophisticated detection technologies have recently exposed the high prevalence of preinvasive colorectal neoplasia in the adult U.S. population. Although cancer screening and surveillance provide opportunities for risk stratification, they achieve risk reduction only when coupled with effective interventions. This review surveys the lead compounds for colorectal cancer prevention and the measures by which they may be prioritized for clinical testing. Clinical trials remain the rate-limiting step in agent development, and novel trial designs are needed to hasten agent identification and testing for cancer prevention. Innovative research models include the nesting of prevention end points within cancer treatment trials and within trials testing promising preventive compounds intended for nononcologic indications.

Hereditary colorectal cancer: screening and management

Colorectal cancer (CRC) affects approximately 6% of the US population, with equal distribution between men and women. It is hereditary in a high proportion of cases and is one of the most preventable cancers. Detection and removal of its precursor lesions, the adenomatous polyps, is the foundation of preventive strategies. However, once CRC is diagnosed, surgical resection is the only cure. The likelihood of cure is higher when CRC is diagnosed at an early stage. Dietary and lifestyle modifications have little, if any, impact on CRC. Endoscopy with polypectomy prevents cancer deaths. The most important issues are screening and surveillance by any of the recommended modalities. Remaining concerns include the choice of screening tests, optimal testing intervals, and cost effectiveness. Patients may be stratified by personal and family risk and by the specific strategies used. Newer developments in genetic testing and imaging, including virtual colonoscopy, hold promise for future prevention. Chemoprevention with nonsteroidal anti-inflammatory drugs may have a role in high-risk populations. Colonoscopy is the most effective method of CRC prevention.