PURPOSE: The strongest predictors of renal function after partial nephrectomy (PN) are preoperative GFR and amount of preserved parenchyma.
Measurement of volume preservation with 3D imaging (3DVP) is accurate, but time-consuming. Percent functional volume preservation (PFVP) was designed to replace surgeon assessment of volume preservation (SAVP) with a less labor-intensive, objective assessment. We compared 3DVP, PFVP and SAVP as predictors of renal function after PN.
MATERIALS AND METHODS: 3DVP, PFVP and SAVP were calculated for 41 patients with pre- and post-operative cross-sectional imaging. Internal validation of SAVP was performed for 75 more patients. Short and long-term renal function was assessed with univariable and multivariable linear regression models.
RESULTS: Median parenchymal preservation was 85% by 3DVP (37%-105%), 91% by PFVP (51%-114%), and 88% by SAVP (45%-99%). Each method was strongly correlated with nadir GFR (R2=0.75, 0.65, 0.78, respectively; each p< 0.0001) and latest GFR (R2=0.65, 0.66, 0.67, respectively; each p< 0.0001). Univariable analyses revealed that age, preoperative GFR, RENAL score, and each assessment were significant predictors of renal function (p< 0.05), and parenchymal preservation was the strongest predictor in multivariable analyses (p< 0.0001). Models using 3DVP, PFVP and SAVP were statistically similar in ability to predict nadir GFR and latest GFR. Using an additional validation cohort, SAVP remained strongly correlated with nadir GFR (R2=0.74) and latest GFR (R2=0.73), respectively (p< 0.0001).
CONCLUSIONS: SAVP provides a reliable estimate of renal functional preservation, with comparable characteristics to more time-intensive alternatives. We propose that SAVP reporting should be performed routinely in order to facilitate analysis of PN outcomes.
Written by:
Tobert CM, Boelkins B, Culver S, Mammen L, Kahnoski RJ, Lane BR. Are you the author?
Michigan State University College of Human Medicine, Grand Rapids, MI.
Reference: J Urol. 2013 Nov 7. pii: S0022-5347(13)05897-7.
doi: 10.1016/j.juro.2013.11.003
PubMed Abstract
PMID: 24211601
UroToday.com Renal Cancer Section
