BACKGROUND Obesity has a significant association with renal cell carcinoma (RCC). Surgery is the preferred treatment of demarcated RCC. Obesity increases the complexity of surgical outcomes. There is a paucity of data regarding surgical technique outcomes in obese patients. OBJECTIVE We investigated short- and long-term renal outcomes in obese patients post-RCC surgery through open, laparoscopic, or robotic partial nephrectomy. METHODS This is a retrospective chart review of obese patients after open, laparoscopic, or robotic partial-nephrectomies over 12 years at a single center. The obese (BMI ≥ 30) and the non-obese (BMI< 30) patients were studied in 2-time frames: short (3-6 months post-surgery), or long (> 6 months) and followed up to 4 years. RESULTS Of the 140 patients, 75 were obese and 65 were non-obese. In the obese, 3-6 months after minimally-invasive surgery, the odds of having a decrease or no change in creatinine values were 0.62 times lower compared to open surgery. Over 6 months after minimally-invasive surgery, the odds were 1.24 times higher. Neither of these results were statistically significant. In the non-obese group, at 3-6 months after minimally-invasive surgery, the same odds were 4.86 times higher. This was statistically significant (P<0.05). Over 6 months after minimally invasive surgery, the odds were 4.13 times higher. This was not statistically significant. CONCLUSIONS We observed non-statistically significant preservation of renal function in obese patients undergoing OPN at 3-6 months postoperatively. Conversely, after 6 months, the same was true for MIPN, indicating a long-term benefit of MIPN. In the non-obese, MIPN was favored over OPN. CLINICALTRIAL na

Background Obesity is significantly associated with renal cell carcinoma. Surgery is the preferred treatment for demarcated lesions of renal cell carcinoma; however, obesity increases the complexity of surgical outcomes. Minimally invasive surgical techniques are preferred over open partial nephrectomy (OPN), but controversy remains regarding the most efficacious technique in patients with obesity. Objective This study aims to determine whether minimally invasive partial nephrectomy (MIPN) or OPN better preserves renal function and investigate short- and long-term renal outcomes in patients with obesity undergoing a partial nephrectomy. Methods We conducted a retrospective chart review of 242 adult patients aged ≥18 years who underwent MIPN or OPN between January 1, 2005, and December 31, 2016, at the University of Arkansas for Medical Sciences. Using creatinine as a measure of kidney function, patients’ preoperative levels were compared with their postoperative levels in 2-time frames: short (3-6 months postsurgery) or long (>6 months). The primary outcome was the change in creatinine values from preoperative to >6 months postoperatively in patients with obesity. Secondary outcomes included the change in creatinine values from preoperative to 3 to 6 months postoperatively in patients with obesity who underwent MIPN versus OPN. We also analyzed the creatinine values of nonobese patients (BMI <30) who underwent partial nephrectomy using the same time frames. Unconditional logistic regression was used to estimate crude and multivariable-adjusted odds ratios (ORs) and 95% CI to observe associations between surgery type and changes in creatinine values from while stratifying for obesity. Results A total of 140 patients were included in the study, of whom 75 were obese and 65 were nonobese. At >6 months after MIPN (n=20), the odds of patients with obesity having a decrease or no change in creatinine values was 1.24 times higher than those who had OPN (n=13; OR 1.24, 95% CI 0.299-6.729; P=.80). At 3 to 6 months after MIPN (n=27), the odds were 0.62 times lower than those after OPN (n=17; OR 0.62, 95% CI 0.140-2.753; P=.56). In the nonobese group, at 3 to 6 months after undergoing minimally invasive surgery (n=18), the odds of having a decrease or no change in creatinine values was 4.86 times higher than those who had open surgery (n=21; OR 4.86, 95% CI 1.085-21.809; P=.04). At more than 6 months after MIPN (n=14), the odds were 4.13 times higher than those after OPN (n=11; OR 4.13, 95% CI 0.579-29.485; P=.16). Conclusions We observed a nonstatistically significant preservation of renal function in patients with obesity who underwent OPN at 3 to 6 months postoperatively. Conversely, after 6 months, the same was true for MIPN, indicating the long-term benefit of MIPN. In the nonobese group, MIPN was favored over OPN.