How often should patients be sigmoidoscoped? A mathematical perspective

Colorectal Cancer Prevention in Lung Transplant Recipients: The Need for an Enhanced Surveillance Protocol

BACKGROUND

Solid organ transplant recipients are at increased risk for noncutaneous neoplasms, including colorectal cancer (CRC). We evaluated precancerous lesions detected by post-transplant surveillance colonoscopy to infer the rate at which new adenomas develop in this population.

STUDY DESIGN

We reviewed all patients who underwent lung transplant between January 2013 and August 2017 at our institution. Those with post-transplant survival <1 year, personal history of CRC, previous lung transplant, and lack of pretransplant colonoscopy were excluded.

RESULTS

During the study period, 411 patients underwent lung transplant; 237 met inclusion criteria. Median age at transplant was 63.6 (interquartile range [IQR] 59.2-68.3) years. Most recipients were immunosuppressed with a combination of prednisone, tacrolimus, and mycophenolate mofetil. At least 1 adenoma was found in 92 patients (38.8%) pretransplant and in 118 patients (49.8%) from 1 to 5 years post-transplant, with 68.6% identified at 1 year. Most adenomas were identified proximal to the splenic flexure. Multiple (≥3) adenomas were found in 31.4% of positive colonoscopies. Within 5 years after transplant, patients with a positive pretransplant colonoscopy had significantly more positive post-transplant colonoscopies than patients with a negative pretransplant colonoscopy (63.0% vs 41.4%, p < 0.001). No de novo CRC was identified.

CONCLUSIONS

Lung transplant recipients have a significantly higher risk of adenoma formation than average-risk adults (25%-30% national detection rate). This increase occurs in the early post-transplant period (within 3 years). An enhanced CRC surveillance protocol for lung transplant recipients is needed.

The incidence of colorectal cancer following a negative screening sigmoidoscopy: implications for screening interval

BACKGROUND & AIMS

Current guidelines recommend a 5-year interval for colorectal cancer (CRC) screening by sigmoidoscopy. However, the optimal screening interval is uncertain. We estimated the annual incidence of distal and proximal CRC in the first 5 years following a negative sigmoidoscopy examination to gauge the potential benefit of rescreening in <5 years.

METHODS

A cohort of 72,483 participants in the Colon Cancer Prevention program of Kaiser Permanente of Northern California (KP) was defined using computerized databases. Men and women aged 50 years and older who had a negative screening flexible sigmoidoscopy examination between 1994 and 1996 and were considered not to be at high risk for developing CRC were included. Subjects were censored at the time of diagnosis (for cases), death, termination of KP membership, or subsequent colon examination.

RESULTS

Thirty cases of distal and 80 cases of proximal CRC occurred. Age-adjusted incidence rates of distal CRC ranged from a low of 2.8 per 100,000 person-years in the first year of follow-up to a high of 13.0 per 100,000 in the fourth year (rate difference, 10.2; 95% confidence interval, 1.1-19.3). However, for the entire follow-up period, incidence of distal CRC remained much lower than age-adjusted rates of 70.6 in the general population (Surveillance, Epidemiology, and End Results registry). The incidence of proximal CRC was also decreased modestly over population rates of disease.

CONCLUSIONS

Screening by sigmoidoscopy more frequently than every 5 years would likely lead, at best, to only modest improvements as compared with a 5-year screening interval.

Colorectal polyps in the elderly: what should be done?

Colorectal cancer is an important cause of morbidity and mortality among Western nations, and is more common in the elderly than in younger individuals. With the general acceptance of the adenoma-carcinoma sequence, the current consideration is that colorectal cancer is preventable if all adenomas are removed before they have the chance to progress to cancer. To that end, physicians should now advocate screening for colorectal cancer and through this effort a large number of patients with adenomatous polyps will be discovered. It is important to understand the strategy in dealing with this growing population of patients with adenomas. After an initial polypectomy, patients with adenomas should be entered into a surveillance program to detect and remove recurrent adenomas. Recommended surveillance intervals are shorter for patients with a family history of colorectal cancer, those with multiple adenomas (>2), large adenomas (> or = 1cm), or those whose adenomas have high-grade dysplasia, villous architecture, or that are cancerous. Effective chemoprevention would be a potential method of lengthening colonoscopic surveillance intervals. Unfortunately, no treatment has been found to be effective enough to alter our current surveillance practice. The only recommendation that can be made at this time for those patients with a history of colonic adenomas is to add 3 g/day of calcium carbonate to their diet, though its effect on adenoma recurrence is modest.

Approach to colon polyps in the elderly

Colorectal cancer is a common but potentially preventable disease. Nearly all colorectal cancers are thought to arise from adenomatous polyps. The conclusions from the National Polyp Study strongly support the concept that the removal of polyps may prevent the future development of colorectal cancer. With the growing acceptance of screening for colorectal cancer, many elderly patients with adenomatous polyps will be discovered. Because increasing age is a powerful determinant of a higher prevalence of colonic neoplasia in asymptomatic individuals, physicians will need to be prepared to make informed decisions regarding the treatment of elderly patients with colonic polyps. The literature is reviewed and guidelines are formed regarding the optimal surveillance interval for patients with colonic polyps. The age at which surveillance and screening for colorectal neoplasia should stop is also reviewed. Conclusions are based on the currently available data.

Metachronous colorectal carcinoma

During the period 1943-67, 903 Danish patients aged less than 40 years had colorectal carcinoma. The patients were followed up for up to 41 years and during this period 44 of 501 (9 per cent) operated on for cure developed a metachronous colorectal carcinoma. The cumulative risk of a metachronous colorectal carcinoma was 30 per cent after up to 41 years of observation. The occurrence of a metachronous colorectal carcinoma was evenly distributed in the observation period. The cumulative survival rate after operation for a metachronous colorectal carcinoma was 41 per cent after 20 years of observation. We propose a lifelong follow-up programme after resection of colorectal carcinoma for cure in this age group, including annual Hemoccult test and colonoscopy at 3-year intervals.