Functional Outcomes of Robot-Assisted and Laparoscopic Partial Nephrectomy for cT1a and cT1b Renal Neoplasia with Low-Intermediate Tumor Complexity: Do Mass Localization, Ischemia, and Surgical Approach Matter?

Background: Nephron-sparing surgery is the gold standard for the treatment of cT1 renal neoplasms. The literature extensively debates the impact of various surgical techniques on long-term renal function, focusing particularly on ischemic damage and warm ischemia time (WIT). "Residual vascularized parenchymal volume" has emerged as a key factor influencing renal function outcomes. This study investigates the role of tumor localization and surgical technique (on-clamp versus off-clamp) in renal functional recovery for patients with low-to-intermediate tumor complexity underwent both robotic and laparoscopic partial nephrectomy. Patients and methods: A multicenter retrospective study was conducted on 100 patients with cT1a or cT1b renal tumors (RENAL score 4-9) who underwent robotic or laparoscopic partial nephrectomy between 2020 and 2024. Demographic, tumor, and perioperative data were collected. Trend of serum creatinine and estimated glomerular filtration rate (eGFR) was evaluated at baseline, immediately postsurgery, and at 1, 3, 6, and 12 months. Statistical analysis was performed using Mann-Whitney U, chi-square, and Spearman's rank correlation tests. Results: No significant differences in renal function were found between cT1a and cT1b tumors or between on-clamp and off-clamp techniques. The robotic and laparoscopic approaches also showed no significant difference in long-term renal outcomes. Conclusions: Tumor localization, ischemia type, and surgical approach did not significantly impact functional outcomes in low-to-intermediate complexity cT1 renal tumors. Comparable renal recovery was observed with both on-/off-clamp and robotic/laparoscopic techniques, as long as ischemia remained under 30 min. In this setting, the ischemic strategy may be chosen to enhance visibility and maximize parenchymal preservation.