Impact of pre-existing diabetes mellitus on survival in stage I renal cell carcinoma.

676 Background: AUA guidelines recommend consideration of nephron sparing surgery in patients with comorbidities that are likely to impact renal function, such as diabetes mellitus (DM). We compared the impact of partial nephrectomy (PN) and radical nephrectomy (RN) on overall survival (OS) in patients with pre-existing DM and Stage I Renal Cell Carcinoma (RCC). Methods: Multicenter retrospective analysis of surgically treated Stage I RCC from 2005-16 with or without DM. Primary outcome was OS analyzed by DM+ or DM- and surgical approach (PN or RN) for AJCC Stage I. Logistic (OR) and Cox (HR) regression were utilized for OS. Results: 2173 patients were analyzed (1223 RN, 1819 PN, 555 DM+, 2487 DM-) with mean follow-up of 49.1 months. Increasing Age (OR 1.028, p = .009), RN (OR 2.446, p = .001), and most recent eGFR < 45 (OR 2.306 p = .002) remained significant on multivariate analysis for OS (Table 1). In the PN subgroup, DM+ or DM- was not associated with decreased OS (HR 1.48 p = 0.19). DM+ was associated with decreased OS in the RN subgroup (HR 1.97 p = 0.005). Conclusions: In Stage I RCC, DM and RN negatively impacted OS, while only RN remained significant on MVA. Subgroup analysis of PN showed that OS was similar in DM- and DM+ patients, but diagnosis of DM had a profound impact on OS in the RN group. This supports the guideline statements and offers evidence that urologists should prioritize nephron sparing surgery in patients with DM and Stage I Renal Cell Carcinoma.[Table: see text]