Introduction: The role of partial nephrectomy (PN) is not well defined for cT2 renal cell carcinoma (RCC) as compared to radical nephrectomy (RN). The aim of this study was to examine oncological outcomes of PN as compared to RN for non-metastatic cT2 RCC. Methods: The Canadian Kidney Cancer information system was used to define patients who underwent surgery for non-metastatic cT2 RCC from January 2011 to October 2022. Patients with clear-cell, papillary, and chromophobe RCC were included. Other histology, multiple tumours, and hereditary RCC syndrome patients were excluded. Each PN patient was individually matched to RN up to 1:4 depending on availability of patients based on tumor size (+/- 1cm), histology, grade (clear cell and papillary), and necrosis (clear cell). Matched patients were analyzed as clusters. Results: A total of 1523 patients were identified, and 50 PN patients met study criteria who were then matched to 185 RN patients. Both groups had similar age, gender, smoking status, BMI, Charlson comorbidity index score, symptoms at presentation, baseline eGFR, hemoglobin and pathological characteristics. PN patients had smaller tumors (7.6 cm [IQR 23] vs 8.4 [IQR 2.4], p=0.0479), had higher likelihood of undergoing open surgery (72.9% vs 31.8%, p<0.0001) and less likely received adrenalectomy (2% vs 24.3%, p=0.0004). Positive surgical margin rates were similar in both groups (8.2% in PN vs 3.4% in RN, p=0.2296). Median follow up was not significantly different in either group (3.6 yrs [IQR 4.7] in PN vs 3.3 [4.7] yrs in RN, p=0.975). During the follow up period, PN patients had higher risk of local recurrence (HR 3.0, 95%CI 1.08-8.37) and lower risk of metastasis (HR 0.36, 95%CI 0.15-0.88), overall survival (HR 0.36, 95%CI 0.18-1.78) as compared to RN. Cancer specific recurrence was similar between both groups (HR 0.56 ,95%CI 0.18,1.78). PN patients preserved more GFR than RN patients (-14.4 [SD 17.9] vs -23.7[SD 15], p=0.0006). Complications rates were similar between PN and RN (18% vs 8.65%, p=0.0571). Conclusions: In this multi-institutional Canadian cohort of patients with non-metastatic cT2 RCC undergoing surgery, PN compared to RN was associated with higher local recurrence, lower risk of distant metastasis, and death from any cause with similar complications and better preservation of renal function. Despite individual patient matching, there is likely unadjusted selection bias resulting in superior cancer survival associated with PN. SOURCE OF Funding: N/A
