Mp75-06 National Outcomes in Postoperative Complications and Readmission Rates Following Open and Minimally Invasive Nephrectomy

Abstract

INTRODUCTION AND OBJECTIVES:The incidence of renal masses has been increasing steadily in recent years, in part due to the widespread use of cross sectional imaging. Interestingly, the prevalence of obesity is on the rise as well suggesting a potential link between the two trends. In the present study we aim to investigate the potential association between BMI and clinico-pathological features of localized renal masses.METHODS: An international, multi-institutional retrospective review of patients that underwent surgery for clinically localized renal masses between 2000 and 2010 was undertaken following an IRB approval. Patients were divided into four BMI groups: A (BMI<25), B (BMI 25-27.9), C (BMI 28-31.9) and D (BMI32). The variables compared between the groups included: renal mass pathological diagnosis, renal cell carcinoma (RCC) subtype, Fuhrman grade and clinical stage. Fuhrman grade was divided into 2 categories: low (grades 1-2) and high (grades 3-4). Differences between groups were evaluated with Fisher 0 s exact test and Cochran-Armitage trend test. Statistical significance was set at p<0.05.RESULTS: A total of 1,750 patients with a median BMI of 28 (IQR 25-32). Benign masses accounted for 17% and RCC for 83% of cases with similar proportion across BMI groups (p¼0.4). The most common subtype was clear cell (76%) followed by papillary carcinoma, chromophobe and other subtypes (18%, 3% and 3% respectively). Subtype distribution was comparable across BMI groups (p¼0.7). Similarly, clinical stage distribution was comparable to the overall cohort with T1a, T1b, T2a and T2b accounting for 47%, 30%, 14% and 9%, respectively. The distribution of Fuhrman grade in RCC, however, demonstrated an increased proportions of low grade with increasing BMI (p<0.05) (Figure 1). This trend was maintained in subgroups according to gender, stage and age (p<0.05 in all subgroup analysis).CONCLUSIONS: In this international multi-institutional study higher BMI was associated with lower grade of RCC in clinically localized renal masses. This may, in part, explain better survival rates in patients with higher BMI and may correlate with possible link between adipose tissue and RCC biology.