Predicting the risk of pT3a stage in cT1 clear cell renal cell carcinoma

We hypothesized that pT3a stage at nephrectomy can be accurately predicted in cT1N0M0 clear cell-renal cell carcinoma (cc-RCC) patients. Of 236 patients, treated with either partial or radical nephrectomy (2005-2019), 25 (10.6%) harbored pT3a stage. Multivariable logistic regression models predicting pT3a were fitted using age, tumor size, tumor location and exophytic rate. The new model was 81% accurate. In calibration plots, minimal departures from ideal prediction were recorded. In decision curve analyses, a net-benefit throughout all threshold probabilities was recorded relative to the treat-all or treat-none strategies. Using a probability cut-off of 21% for presence of pT3a stage, 38 patients (16.1%) were identified, in whom pT3a rate was 36.8%. Conversely, in 198 patients (83.9%) below that cut-off, the rate of pT3a was 5.6%. Alternative user-defined cut-offs may be selected. The new model more accurately identifies a subgroup of cT1N0M0 cc-RCC patients with substantially higher risk of pT3a stage than average. (C) 2020 Elsevier Ltd, BASO similar to The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.