Functional and Oncologic Outcomes in Single-Kidney Patients Treated with Robot-Assisted Partial Nephrectomy for Renal Tumors: Results from a Prospectively Maintained Dataset of a Single Tertiary Referral Center

<b>Background</b>: Renal tumors in solitary kidneys require treatments that optimize both oncological and functional outcomes. Robot-assisted partial nephrectomy (RAPN) offers a balance between these needs and reduced morbidity. This study investigates the oncologic and functional outcomes of RAPN in solitary-kidney patients. <b>Methods</b>: We analyzed data from 1852 patients with cT1-T4N0M0 renal cell carcinoma treated by RAPN from January 2018 to June 2022. The cohort included patients with solitary kidneys based on preoperative characteristics, tumor staging and perioperative outcomes using the Trifecta criteria. <b>Results</b>: Of the study participants, 39 had solitary kidneys. Fifteen patients (38.6%) had an ASA score > 2, indicating a higher preoperative risk. The median PADUA score was 7 (IQR 8-9). Moreover, 28 (71.8%) patients had a chronic kidney disease stage > 2. Trifecta success was achieved in 26 (66.6%) of the cases. During a median follow-up of 36 months, tumor recurrence was observed in 12 patients (30.7%), with local recurrences in 4 (10.2%) and systemic recurrences in 8 (20.5%). A higher ASA score and global ischemic clamping were independent predictors of renal function decline at the third postoperative day and Trifecta failure. Only a higher ASA score significantly predicted a significant long-term decline in renal function. Nucleolar grade at pathological stage was the only factor significantly associated with tumor recurrence. <b>Conclusions</b>: RAPN is as an effective treatment for renal tumors in solitary kidneys, balancing oncological control and renal function preservation. Global ischemia and patient physical status are the most important factors influencing outcomes and highlight the importance of patient selection and tailored surgical strategies.