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Dialysis patients over-screened for colorectal cancer

The rate of colon cancer screening remains high among patients receiving maintenance dialysis, despite American Society of Nephrology recommendations against routine cancer screening in this patient population because it does not improve survival.

“Prior studies have demonstrated that screening for colon cancer failed to provide patients on dialysis a substantial survival benefit due to the high risk of mortality associated with [end-stage renal disease (ESRD)],” Christopher A. Carlos, MD, from the University of California, San Francisco, and colleagues wrote. “Although a growing body of literature has shown potentially inappropriate colorectal cancer screening in various populations no studies have documented the rate of colorectal cancer screening specifically among patients with ESRD.”

Researchers examined a cohort of 469,574 Medicare patients aged 50 and older who received dialysis between Jan. 1, 2007, and Sept. 30, 2012, to determine the rate of cancer screening inappropriately targeted toward patients with limited life expectancy on dialysis. They assessed colorectal cancer screening tests according to quartiles of risk of mortality and kidney transplant using multivariable Cox modelling.

Carlos and colleagues found that over a median follow-up period of 1.5 years, 11.6% of patients received a colon cancer screening test (57.9 tests per 1000 person-years). The results showed that incidence rates of colonoscopy, flexible sigmoidoscopy and fecal occult blood test were 27.9, 0.6 and 29.5 per 1,000 person-years, respectively. Patients in the lowest quartile of mortality risk had a 33% higher rate of screening compared with patients in the highest quartile (HR = 1.53; 95% CI, 1.49-1.57; 65.1 vs. 46.4 tests per 1,000 person years). Compared with patients least likely to receive transplant, those most likely to receive transplant were also more likely to be screened (HR = 1.68; 95% CI, 1.64-1.73).

“Although more screening tests, particularly colonoscopy, were performed among healthier ESRD patients, overall rates suggest the potential for a substantial degree of testing that would not lead to added survival benefit,” Carlos and colleagues wrote. “Future studies might be considered to assess the impact of the ABIM’s Choosing Wisely campaign and similar initiatives to reduce waste in the health care system by targeting screening to individuals most likely to benefit.” – by Savannah Demko

Disclosure: Carlos reports no relevant financial disclosures.