Introduction

While partial nephrectomy (PN) is an accepted standard for small renal mass, utilization for large (>7cm) renal mass is controversial. We conducted a comparative analysis of survival and functional outcomes of PN and radical nephrectomy (RN) for clinical T2 Renal Mass (cT2RM).

Methods

Retrospective international multicenter analysis of PN and RN for cT2RM (T2N0M0) from 1987-2016. Primary outcome was change in glomerular filtration rate (delta eGFR). Secondary outcomes were de novo Stage 3 Chronic Kidney Disease (CKD, eGFR<60), eGFR<45 at last follow up, overall survival (OS), and complication rates. Multivariable (MV) logistic regression was used for outcomes, and Kaplan-Meier (KM) curves were created for OS.

Results

Study cohort with 1125 patients (239 PN, 886 RN), mean age 60.3 years, median follow up 38.9 months, mean clinical tumor size 9.9 cm, 70.5% cT2a / 29.5% cT2b. PN had higher BMI (29.6 vs. 27.3, p<0.001), as well as higher rate of hypertension (HTN, 59% vs. 47%, p=0.001) and diabetes (DM, 20.9% vs. 13.4%, p=0.005). RN cohort had larger tumor size (10.0 vs. 9.2 cm, p<0.001) and more cT2b disease (32.6% vs. 18.0%, p<0.001). Mean ischemia time for PN was 34.6 min. No significant differences were noted in hospital stay (p=0.697) or 30 day complications (36.0% vs. 36.9%, p=0.821). RN had higher all-cause mortality rate (32.6% vs. 13.4%, p<0.001). KM analysis revealed 5 year OS of 66.9% for RN and 82.2% for PN (p<0.001). KM stratified by cT stage PN vs. RN revealed 5 year OS for cT2a (83.2% vs. 70.1%, p=0.004) and for cT2b (84.6% vs. 60.2%, p=0.003) (figure). Preoperative eGFR was similar (79.4 vs. 77.3, p=0.23), and mean delta eGFR was higher for RN (-20.2 vs. -10.4, p<0.001). RN had worsened renal functional outcomes with respect to de novo GFR <60 (51.2% vs. 28.9%, p<0.001) and de novo GFR <45 (22.8% vs. 14.0%, p<0.001). MV Cox model for OS was significant for age (HR 1.02, p<0.001), DM (HR 1.54, p=0.021), tumor grade 3/4 (HR 2.22, p<0.001), lymphovascular invasion (LVI, HR 1.74, p=0.001), and RN (HR 3.24, p<0.001).

Conclusions

PN when performed in the setting of cT2RM provides renal functional benefit and may have survival benefit. Consideration may be given to PN when technically feasible for cT2RM in appropriately selected patients. Prospective data are requisite to confirm.

Funding

Stephen Weissman Kidney Cancer Research Fund. NIH grants UL1TR000100 and UL1TR001442.