Chronic kidney disease (CKD) may increase the risk for recurrence and progression of non-muscle invasive bladder cancer (NMIBC) following transurethral resection, according to researchers.
“CKD is an independent predictor of recurrence and progression in primary NMIBC,” lead investigator Tetsutaro Hayashi, MD, PhD, of Hiroshima University in Hiroshima City, Japan, told Renal & Urology News. “Adding CKD stage to the conventional risk factors could improve the accuracy of risk stratification.”
Dr Hayashi and colleagues and colleagues analyzed oncologic outcomes by CKD stage for 418 Japanese patients who underwent transurethral resection for NMIBC from 2006 to 2013. According to the Japanese Society of Nephrology’s estimated glomerular filtration rate (eGFR) equation, 68.7% of patients had G1-2, 23.4% had G3a, and 7.9% had G3b–5 CKD.
Recurrence developed in 57% of patients, and progression occurred in 7.7%, according to results published in the International Journal of Urology (2017;24:594-600). Over a median 40 months, T1 tumors were found in higher proportions of patients with worse renal function: 29.6% of G1–2 vs 43.9% of G3a vs 51.4% of G3b–5. Histologic grade 3 tumors also were more common among G3a and G3b–5 patients.
Higher-stage CKD patients had worse recurrence-free and progression-free survival and significantly shorter times to recurrence and progression. On multivariate analysis, CKD stage G3b–5 (eGFR below 45 mL/min/1.73m2) independently and significantly predicted a nearly 2-fold increased risk of recurrence and 3-fold increased risk of progression compared with a CKD stage less than G3b. The team also found that CKD stage correlated well with bladder cancer risk groups based on criteria in the European Association of Urology guidelines.
Among plausible mechanisms linking CKD with NMIBC outcomes, the team speculated that cytokeratin 18, active in inflammation, might increase cancer activity. They also considered the possibility that CKD reflects other factors, such as aging, diabetes, and hypertension. Proteinuria assessed by dipstick testing did not appear predictive in this study. Chronic urinary retention was not assessed.
Kobatake K, Hayashi T, Black PC, et al. Chronic kidney disease as a risk factor for recurrence and progression in patients with primary non-muscle-invasive bladder cancer. Int J Urol 2017;24:594-600. doi: 10.1111/iju.13389.