The hypothesis that renal function could influence oncological outcomes is supported
by anecdotal literature.
To determine whether estimated glomerular filtration rate (eGFR) is related to cancer-specific
mortality (CSM) in patients who had undergone surgery for renal cell carcinoma (RCC).
Design, setting, and participants
A retrospective analysis of 3457 patients who underwent radical (39%) or partial nephrectomy
(61%) for cT1–2 RCC between 1990 and 2015.
Outcome measurements and statistical analysis
The eGFR was calculated by the Chronic Kidney Disease Epidemiology Collaboration equation.
CSM was analyzed in a multivariable competing-risk framework, estimating the subdistribution
hazard ratio (SHR) accounting for deaths from other causes. The relationship between
eGFR and CSM was investigated from multiple statistical approaches—extended Cox regression
with eGFR incorporated as a time-dependent covariate, landmark analysis, and joint
modeling. Other predictors were selected by competing-risk random forest method and
Results and limitations
The relationship between eGFR and CSM was graphically described by a linear spline,
i.e. a continuous piecewise linear function with two lines joined by a knot. For eGFR
treated as a time-dependent covariate, the knot was located at 65 ml/min; at landmark analysis with eGFR at the baseline, 12 mo, and last functional
follow-up, the knots were 85, 60, and 65 ml/min, respectively. In multivariable competing-risk analysis, CSM was associated
with eGFR only for values of eGFR below these cutoffs, with SHRs for every 10 ml/min of reduction in eGFR of 1.25 (p = 0.003), 1.16 (p = 0.028), 1.44 (p = 0.02), and 1.16 (p = 0.042), corresponding to time-dependent eGFR, and eGFR at baseline, 12 mo, and last
functional follow-up, respectively. Joint modeling confirmed these results. A retrospective
design with inherent biases in data collection represents a limitation.
In patients undergoing surgery for RCC, renal function should be preserved in order
to improve cancer-related survival.
The relationship between renal function and probability of dying due to renal cancer
is complex. The present study found a correlation between glomerular filtration rate
and cancer specific mortality that could reconsider the oncological role of renal
function in patients undergoing surgery for renal cancer.