Framing Surgical Decisions in Elderly Patients: Minimally Invasive Partial Versus Radical Nephrectomy for Stage I Renal Cell Carcinoma at Mid-Term Follow-Up

<b>Background/Objectives</b>: The optimal surgical approach for stage I renal cell carcinoma (RCC) in ultra-octogenarians remains debated, especially when balancing oncologic control, renal preservation, and procedural safety. While ablative techniques and active surveillance are often favored in frail patients, robust comparative evidence supporting nephron-sparing surgery in this age group is limited. <b>Methods</b>: We retrospectively reviewed consecutive patients aged ≥80 years who underwent minimally invasive surgery for cT1 clear cell RCC at a high-volume tertiary-care center between July 2001 and August 2025. Patients were stratified into two cohorts: minimally invasive partial nephrectomy (MIPN, <i>n</i> = 51) and radical nephrectomy (MIRN, n = 26). All MIPNs were performed using an off-clamp approach. Baseline, perioperative, functional, and oncologic outcomes were compared. Kaplan-Meier analysis estimated overall survival (OS), cancer-specific survival (CSS), and progression to significant chronic kidney disease (sCKD, defined as CKD stage ≥ 3b). <b>Results</b>: Groups were comparable in age, comorbidities, and ASA score. MIRN patients exhibited higher tumor complexity (RENAL score: 9 vs. 7, <i>p</i> = 0.01) and a greater proportion of pT1b lesions (77% vs. 37.3%, <i>p</i> = 0.01). Perioperative transfusions occurred exclusively in the MIRN group (<i>p</i> = 0.01), whereas complication rates were low and similar between groups. MIPN was associated with significantly higher eGFR at follow-up (48 vs. 30.9 mL/min/1.73 m², <i>p</i> = 0.01) and a delayed progression to sCKD (<i>p</i> = 0.01), with no differences in OS or CSS at a median follow-up of 30.5 months. <b>Conclusions</b>: In this real-world series of ultra-octogenarians with cT1 clear cell RCC, off-clamp minimally invasive partial nephrectomy ensured superior renal function preservation and delayed progression to sCKD, without compromising oncologic control at mid-term follow-up. Beyond statistical outcomes, these results underscore the importance of tailoring surgical strategies to protect long-term functional autonomy and preserve physiological resilience in elderly patients.