Comparison of Trifecta and Pentafecta Outcomes between T1a and T1b Renal Masses following Robot-Assisted Partial Nephrectomy (RAPN) with Minimum One Year Follow Up: Can RAPN for T1b Renal Masses Be Feasible?

PURPOSE/OBJECTIVES: To investigate the feasibility of RAPN on T1b renal mass by assessment of Trifecta and Pentafecta rate between T1a and T1b renal mass. MATERIALS/METHODS: We retrospectively reviewed the medical records of 277 cases of RPN performed from 2006 to 2015. Sixty patients with clinically T1b renal masses (> 4cm and ≤ 7 cm) were identified, and from 180 patients with clinically T1a renal mass, 60 patients were matched with T1b renal mass by propensity score. Tumor complexity was investigated according to R.E.N.A.L nephrometry score. “Pentafecta” was defined as achievement of Trifecta (negative surgical margin, no postoperative complications and warm ischemia time of ≤ 25 minutes) with addition of over 90% estimated GFR preservation and no chronic kidney disease stage upgrading at 1 year postoperative period. Propensity score matching was performed by OneToManyMTCH. Logistic regression models were used to identify the variables which predict the Trifecta, and Pentafecta ac. RESULTS: Preoperative variables (age, sex, body mass index, ASA score) were similar between T1a and T1b after propensity score matching. The median R.E.N.A.L. nephrometry score was 8 vs 9 for T1a and T1b respectively (p<0.001). The median warm ischemia time was 20.1 min vs 26.2 min (p<0.001). Positive surgical margin rate was 5% vs 6.6% (p = 0.729) and overall complication rate of 13.3%. vs 15% (p = 0.793). The rate of achievement of Trifecta rate were 65.3% vs 43.3% (p = 0.017) and Pentafecta rate were 38.3% vs 26.7% (p = 0.172). For achievement of Pentafecta, R.E.N.A.L nephrometry score (HR 0.80; 95% CI (0.67–0.97); p = 0.031) was significant predictor of achieving Pentafecta. Subanalyis to assess the component of R.E.N.A.L nephrometry score, L component (location relative to the polar lines, HR 0.63; 95% CI (0.38–1.03); P = 0.064) was relatively important component for Pentafecta achievement. CONCLUSIONS: The rate of Pentafecta after RAPN was comparable between T1a and T1b renal masses. RAPN is a feasible modality with excellent long term outcome for patients with larger renal mass (cT1b).