Optimal thresholds for the distance between tumor and collecting system predicting collecting system opening and trifecta achievement in RAPN.

BACKGROUND: We examined the clinical significance of the distance between the tumor and collecting system or sinus (DTCS), representing the nearness (N) score in the RENAL nephrometry score, on outcomes of robotic-assisted partial nephrectomy (RAPN). METHODS: We retrospectively analyzed 425 patients who underwent RAPN between 2016 and 2021. Multivariate binary logistic regression was used to assess predictive preoperative clinical factors. Receiver operating characteristic (ROC) curve analysis determined the optimal DTCS cutoff point for each outcome. RESULTS: The mean DTCS was 4.0 mm (SD 4.6), and 79 were N1, 97 N2, and 249 N3. DTCS was significantly associated with opening of the collecting system (p < 0.001) and trifecta achievement (p = 0.085), but not with pentafecta achievement. Optimal DTCS cutoff values were 4 and 7 mm for opening of the collecting system, and 0 mm for trifecta achievement. CONCLUSIONS: While the DTCS cutoff value of 4 and 7 mm may indicate surgical technical difficulty, the 0 mm appears to be the more clinically relevant cutoff value for perioperative outcome risk stratification.