RCC Incidence Higher Among Dialysis Patients
SEATTLE — Patients with end-stage renal disease (ESRD) had a prevalence of 0.5% of renal cell carcinoma (RCC), according to findings presented at the 33rd Annual Dialysis Conference.
The findings, reported by researchers from Kaiser Permanente Northern California, emerged from a study of 6,827 ESRD patients undergoing dialysis from 1999-2008.
“The prevalence of RCC in Kaiser Permanent Northern California was 0.5% during the past decade, similar to the previously reported prevalence rate for prevalent dialysis patients, but higher than the reported prevalence in the general population,” said study investigator Sijie Zheng, MD, PhD, an attending physician at The Permanente Medical Group, Kaiser Oakland Medical Center, Oakland, Calif.
Study subjects were aged 18-80 years at dialysis initiation and had been on dialysis for at least six months. Investigators retrospectively followed up patients until their death or the end of the study period on December 31, 2010.
Of the 6,827 patients, 163 were diagnosed with a renal mass or RCC. The majority of the RCC cases were low grade and 30% of them were detected incidentally. The researchers excluded patients who had a bilateral nephrectomy prior to starting dialysis, those diagnosed with RCC before dialysis initiation, and those who lacked a biopsy. Biopsy-proven RCC was found in 35 patients (0.5%). The annual RCC incidence ranged from 0.3% to 0.8%.
Dr. Zheng's team had expected to find a higher incidence of RCC, but noted that the 0.5% prevalence was similar to what had been reported in dialysis patients early in the last decade. Since then, few studies have re-examined the prevalence and incidence of RCC in ESRD patients, Dr. Zheng noted.
Of the 35 subjects with RCC, 13 (37%) were women, 11 (31%) were black, 11 (31%) were Hispanic, nine (26%) were white, and four (11%) were Asian.
The average time from dialysis initiation to RCC diagnosis was 3.4 years and nearly 30% of cases were detected incidentally as a result of a computed tomography scan for unrelated reasons. More than two-thirds of the patients were on hemodialysis at the time of diagnosis; the other patients utilized both peritoneal dialysis and hemodialysis as their renal replacement modality. During the study period, 12 patients died and the median duration between nephrectomy and death was eight months.