ORLANDO, FLA. — Hemodialysis patients with end-stage renal disease have a high risk for colorectal cancer, compared with the general population, Jonathan M. Koff, M.D., reported at the annual meeting of the American College of Gastroenterology.
Patients on dialysis already are known to have an increased risk for hematologic, thyroid, cervical, bladder, kidney, and skin malignancies.
In three separate studies, nephrologists have concluded that colorectal cancer screening is not cost effective in dialysis patients, Dr. Koff said, but that perception could change based on evidence of a high risk of colorectal cancer in such patients, along with growth in the number of patients with end-stage renal disease (ESRD).
In 2001, 96,000 new patients developed ESRD. At that time, about three-fourths of the 406,000 patients who received renal replacement therapy were on dialysis, while the other one-fourth had kidney transplants. The diabetes and metabolic syndrome epidemics may increase the number of patients who receive renal replacement therapy to more than an estimated 2.2 million by 2030, said Dr. Koff of Walter Reed Army Medical Center, Washington.
He and his colleagues conducted a retrospective cohort study of 272,024 patients in the United States Renal Data System, which is managed by the National Institute of Diabetes and Digestive and Kidney Diseases. These patients began dialysis therapy for ESRD between 1995 and 1999 with Medicare as their primary payer.
During the study period, 1.1% of dialysis patients developed colorectal cancer. Dialysis patients had an 82% higher risk of colorectal cancer, compared with age-matched rates in the general population in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database on cancer statistics.
The risk for developing colorectal cancer declined with increasing age; patients aged 30–39 years had the highest risk—more than eightfold higher than the risk for people of the same age in the SEER database.
In a multivariate analysis, advanced age, other malignancy, hemodialysis (rather than peritoneal dialysis), and low hemoglobin and albumin levels were associated independently with an increased risk of colorectal cancer.
Dr. Koff pointed out that he could not independently confirm the diagnoses of colorectal cancer or determine if any of the patients were screened for colorectal cancer before or during the study period.
Only 32% of dialysis patients with colorectal cancer survived 1 year after being diagnosed with cancer; 10% lived 5 years after the diagnosis.
Several different mechanisms could contribute to the increased incidence of colorectal cancer in dialysis patients. Uremia may contribute by causing “functional immunosuppression or decreased tumor surveillance,” Dr. Koff said.
Patients with ESRD may have a lower prevalence of nonsteroidal anti-inflammatory drug use than other patients, according to one study, perhaps providing less chemoprevention, he suggested. Another recent study found that patients with type 2 diabetes who take insulin have a higher risk of colorectal cancer than do similar patients who don't take insulin (INTERNAL MEDICINE NEWS, Nov. 15, 2004, p. 60).