Colon Cancer Screening May Benefit Elderly

This study is the first to address whether or not to screen unscreened elderly patients.

Colorectal cancer screening should be considered in unscreened patients aged 75 years or older, especially those with no comorbid conditions, a new study published in the Annals of Internal Medicine indicates.

Current US Preventive Services Task Force recommendations advise against the routine screening for colorectal cancer in adequately screened people aged 75 years or older. However, this study is the first to address whether or not to screen unscreened elderly patients.

Frank van Hees, MSc, of the Department of Public Health, Erasmus University Medical Center, the Netherlands, and colleagues showed that in healthy unscreened patients colonoscopy can be cost-effective until age 83, sigmoidoscopy until age 84, and fecal immunochemical testing until age 85 or 86 years.

In an editorial that accompanied the article, Amanda V. Clark, MD, and C. Seth Landefeld, MD, of the University of Alabama at Birmingham, called for monitoring and public reporting of screening in this patient population.

“For persons older than 75 years, colorectal cancer screening may be considered an exemplar of the medical ‘green banana’-it takes years to ripen in terms of preventing death, a time that may seem long when life expectancy may be short,” Clark and Landefeld wrote. “In this issue, van Hees and colleagues provide compelling evidence that many older persons should buy the medical green banana of colorectal cancer screening, at least into their 80s.”

Van Hees and colleagues used the Microsimulation Screening Analysis-Colon (MISCAN-Colon) model to calculate the effectiveness and costs of colorectal cancer screening in unscreened patients aged 75 to 90 years. MISCAN-Colon simulates the life histories of a large population from life to death. In this study it was calibrated to the age-, stage-, and localization-specific incidence of colorectal cancer seen in the SEER Program from the late 1970s (when screening was introduced). The researchers then simulated an elderly patient population with no, moderate, or severe comorbidities.

The study intervention was undergoing one-time colonoscopy, sigmoidoscopy, or fecal immunochemical test screening. The researchers made several assumptions, including a 100% compliance rate.

“Patients with an adenoma or colorectal cancer detected during sigmoidoscopy or with a positive fecal immunochemical test result were referred for a diagnostic colonoscopy,” the researchers wrote. “Persons with adenomas detected and removed during a screening or diagnostic colonoscopy were assumed to have colonoscopy surveillance according to the current guidelines. We assumed that surveillance continued until the diagnosis of colorectal cancer or death.”

Analyses showed that the efficacy of screening decreased with increasing age and that the cost of screening increased with increasing age. According to the researchers, the decline in effectiveness is due to increasing risk for death from another cause as age increases, which in turn decreases the chance that screening will prevent death from colorectal cancer. Those patients with no comorbid conditions saw the greatest cost effectiveness of undergoing screening past age 75.

In patients with moderate comorbid conditions, colonoscopy and sigmoidoscopy screening were effective until age 82, and fecal immunochemical testing until age 83 years. Those patients with severe comorbid conditions could undergo cost-effective colonoscopy and sigmoidoscopy until age 79 years and fecal immunochemical testing until age 80 years.