Chronic kidney disease and the risk of incident renal and urothelial cancer in a population-based cohort of 1.2 million adults.

Abstract

351 Background: Prior studies have observed an increased risk of cancer in patients with end stage renal disease, but whether less severe chronic kidney disease influences the risk of cancer is uncertain. Methods: Among 1,190,538 adults at least 40 years of age and no prior dialysis, renal transplant or known cancer who received care within Kaiser Permanente Northern California, we examined the independent association between estimated glomerular filtration rate (eGFR) and the risk of cancer, overall and by type, between 2000 and 2008. Incident cancers were identified from a comprehensive regional cancer registry and potential confounders were ascertained using validated algorithms based on health plan electronic medical records. The impact of time-varying eGFR on incident cancer risk was examined using multivariable extended Cox regression, after excluding any cancers detected during the first two years of follow-up and any eGFR values within 3 months before a cancer diagnosis to reduce potential biases. Results: During 6,000,420 person-years of follow-up, 76,809 incident cancer diagnoses were identified among 72,875 patients (38,744 M, 34,131 F). After adjustment for possible confounding factors, the risk of renal cancer increased with lower eGFR (ml/min/1.73 m2): the adjusted hazard ratio [HR] for renal cancer was 1.35 (95% CI: 1.18–1.55) for eGFR 45–59, HR 1.65 (1.37 to 1.97) for eGFR 30–44, and HR 2.09 (1.62 to 2.70) for eGFR <30. There was a similar association between eGFR and urothelial cancer. However, there was not a significant multivariable association between eGFR and prostate, colorectal, lung, breast, or any cancer. Conclusions: We observed a graded, independent increased risk of renal and urothelial cancer risk with lower eGFR in a large, population-based cohort. However, lower eGFR was not significantly associated with other major cancer types. Additional research is needed to understand potential contributing mechanisms between reduced renal function and renal or urothelial malignancies, as well as whether differential cancer screening strategies are effective in patients with chronic kidney disease.