In patients with chronic kidney disease (CKD), decreasing glomerular filtration rate (GFR) is associated with increased risk of kidney and urothelial cancer in a step-wise fashion, according to a large community-based study. An adjusted multivariate analysis found a 2-fold increase in risk of renal cancer and a substantially increased risk of urothelial cancer at GFR <30 mL/min/1.73 m2. The study was presented at the 2012 ASCO Genitourinary Cancers Symposium, held February 2-4 in San Francisco, California.
“Our study found an increased risk of renal and urothelial cancer with lower GFR rates. This suggests that estimated GFR may play a role in identifying patients with CKD at higher risk of these cancers. We need to assess whether there is a clinical benefit for targeted cancer screenings in this population,” stated William Thomas Lowrance, MD, Huntsman Cancer Institute, University of Utah, who presented the study.
The association between dialysis patients with end-stage renal disease (ESRD) and kidney cancer is well established, with a 3 to 4 times greater risk of kidney cancer. The link between CKD and kidney cancer has been less well studied, Lowrance noted.
About 11.5% of people in the United States have CKD or proteinuria, and 13.5 million Americans have stage 3 CKD or worse. CKD is an independent risk factor for death, cardiovascular events, and hospitalization. About 65,000 new cases of kidney cancer and about 75,000 new cases of urothelial cancer are reported each year. These diseases pose a major health concern.
Using the SEER (Surveillance, Epidemiology, and End Results) registry to capture data from 2000 through 2008, Lowrance and colleagues analyzed Kaiser Permanente members of their renal registry, excluding members with preexisting cancer or ESRD.
Just under 1.2 million adults were included, with a median follow-up of 5.3 years. During that time, more than 76,000 had a new cancer diagnosis. Median age was 55 years, and median age increased with decreasing GFR. Increase in comorbidities was associated with decreasing GFR.
The crude rate of renal cancer increased in a step-wise fashion as GFR decreased.
The same was true for urothelial cancers. In a multivariate analysis adjusted for confounding factors, these results persisted for kidney and urothelial cancers, but no association was seen with breast, lung, colorectal, or prostate cancer.
Lowrance said that one limitation of this study is potential selection bias, since subjects with worse renal function may be followed more closely. Also, there was no adjustment for severity of comorbidities or dosages of medication.
“More study is needed to elucidate the mechanism by which decreased GFR may play a role in development of kidney and urothelial cancers,” he said