Screening colonoscopy may have "modest benefit" in older Medicare population

Last Updated: 2016-09-27

By Will Boggs MD

NEW YORK (Reuters Health) - Screening colonoscopy may modestly reduce colorectal cancer rates among Medicare beneficiaries aged 70 to 79 years, and less so among older individuals, according to an observational study.

"Our findings are consistent with the USPSTF recommendations for routine screening through age 75, followed by individualized decisions afterward," Dr. Xabier Garcia-Albeniz from Harvard T. H. Chan School of Public Health in Boston told Reuters Health by email. "Because the ongoing trials do not include the older age groups, our study provides helpful information for benefit-risk analyses."

The Centers for Medicare & Medicaid Services currently reimburses screening colonoscopies with no upper age limit, Dr. Garcia-Albeniz and colleagues note in a report published September 27 in Annals of Internal Medicine.

The team used data from Medicare beneficiaries to estimate the effectiveness of screening colonoscopy in preventing colorectal cancer among elderly persons with no recent history of colonoscopy, colorectal cancer, or adenomas. They studied the age groups aged 70 to 74 and aged 75 to 79 separately.

In the younger age group, the standardized eight-year risk for colorectal cancer was 2.19% in the screening colonoscopy group and 2.62% in the no-screening group, a significant difference.

In contrast, the eight-year risk for colorectal cancer among individuals aged 75 to 79 years did not differ significantly between those in the screening colonoscopy group (2.84%) and those in the no-screening group (2.97%), according to the report.

The excess 30-day risk for any adverse event requiring hospitalization or an emergency department visit among those undergoing colonoscopy was 5.6 adverse events per 1,000 individuals aged 70 to 74 and 10.3 per 1,000 individuals aged 75 to 79.

The study could not assess potential effects on mortality.

"The follow-up of our study - 25% of individuals were followed for longer than 5.5 years - may be insufficient to detect the full benefits of screening colonoscopy," the researchers note, "although our estimates suggest a colorectal cancer absolute risk reduction at 8 years greater than that found in the screening sigmoidoscopy trials, especially in the younger age group."

"Future research will have to focus on identifying those individuals that will benefit most from screening," Dr. Garcia-Albeniz said. "To identify them, researchers will have to explore not only age, but also different patient characteristics, like family history, sociodemographic characteristics, genetic susceptibility, and so on. Future research will also have to study the optimal intervals between screening tests according to previous findings."

SOURCE: http://bit.ly/2cBaS6s

Ann Intern Med 2016.