New analysis reveals high rate of colon cancer screening among dialysis patients

A new analysis reveals a relatively high rate of colon cancer screening among US patients on dialysis, even though they rarely stand to benefit from such screening. The findings appear in an upcoming issue of the Journal of the American Society of Nephrology (JASN).

Because of the high rates of death among patients receiving dialysis, routine colon cancer screening with colonoscopy does not improve survival for most patients who are not candidates for a kidney transplant. Therefore, as a partner of the American Board of Internal Medicine's Choosing Wisely campaign, the American Society of Nephrology recommends against colon cancer screening among patients receiving maintenance dialysis with limited life expectancy and without signs or symptoms.

A team led by Kirsten Johansen, MD and Christopher Carlos, MD (University of California, San Francisco) looked to see how many US dialysis patients aged ≥50 years were being screened and whether testing was appropriately targeted toward healthier patients on dialysis.

The investigators evaluated 469,574 Medicare beneficiaries receiving dialysis between 2007 and 2012 and ranked them according to their expected survival. Over a median follow-up of 1.5 years, 11.6% of patients received a colon cancer screening. The healthiest quarter of patients were 1.53-times more likely to be screened than the sickest quarter of patients, and those most likely to receive a kidney transplant were 1.68-times more likely to be screened than those least likely to receive a kidney transplant.

Although screening was performed more often among healthier patients, the overall screening rate was fairly high, at a rate of 27.9 colonoscopies per 1000 person-years. This rate is over 8-times higher than the rate of 3.4 per 1000 person-years found among Medicare beneficiaries not on dialysis with similarly limited life expectancies.

"While our findings suggest that the patients with the longest life expectancy and greatest chances of receiving a kidney transplant are the most likely to be screened, there remains a substantial amount of over-screening overall among patients on dialysis," said Dr. Johansen. "Physicians should carefully evaluate patients' prognoses and consider the likelihood that they will truly benefit before ordering screening tests," added Dr. Carlos.

The findings may serve as a starting point for future studies that assess the impact of the Choosing Wisely campaign, which seeks to reduce waste in the healthcare system.