Outcomes and predictors of clinical T1 renal mass (cT1) upstaged to pathological T3a (pT3a) after partial nephrectomy: A single-center experience.

Objectives: Clinical T1 (cT1) renal mass treated surgically has a good prognosis, but there is an upstaging risk that potentially threatens oncological outcomes after partial nephrectomy (PN). We aim to analyze and study the incidence, predictors, perioperative morbidity, and oncological outcomes of pT3a upstaging.

Methodology: A retrospective study of 313 patients who underwent PN for cT1 renal mass at a single center from a single tertiary referral center between 2000 and 2021 was done. Demographic, perioperative, pathological, and outcome variables were reviewed. We compared these parameters between upstaged and non-upstaged groups. Multivariate logistic regression analysis was used to study preoperative variables associated with upstaging.

Results: Nineteen patients were upstaged to pT3a. Making an incidence of 6.1%. Upstaged tumors were bigger (5.02 cm vs. 4.08 cm, p = 0.004), had higher clinical stage T1b (84.2 vs. 40.5%, p < 0.001), had more tumors which were central location (21 vs. 3.4%, p < 0.001), had more endophytic and mesophytic tumors (15.8 vs. 5.8% and 52.6 vs. 9.5%, p < 0.001), and had higher R.E.N.A.L Nephrometry score (8.05 vs. 6, p < 0.001). Upstaged tumors had more operative times (227 vs. 203 min, p = 0.01), more postoperative complications (68.4 vs. 13.1%, p < 0.001), more major complications of Clavien Dindo Grade 3 and above (15.8 vs. 4.4%, p < 0.001). Age (OR 1.035, p = 0.034), Radiological tumor dimension (OR 1.578, p = 0.003), Radiological or Clinical stage (T1b) (9.19, p = 0.008), Higher Nephrometry score (Intermediate and High) (OR 6.184, p = 0.004) were preoperative predictors of upstaging. Oncological outcomes were comparable.

Conclusion: Tumor upstaging was uncommon with more perioperative morbidity. Higher age, larger tumor size, higher tumor stage, and higher nephrometry scores were preoperative predictors of upstaging.