Extreme obesity does not predict poor cancer outcomes after surgery for renal cell cancer

Abstract

ObjectiveTo assess whether extreme obesity (body mass index [BMI] ≥ 40 kg/m 2 ) is associated with peri-operative outcomes, overall survival (OS), cancer-specific survival (CSS), or recurrencefree survival (RFS) after surgical treatment for renal cell carcinoma (RCC). Patients and MethodsAfter institutional review board approval, we used an institutional database to identify patients treated surgically between January 2000 and December 2014 with a pathological diagnosis of RCC. Comprehensive clinical and pathological data were reviewed. Kaplan-Meier analyses were used to estimate OS, RFS and CSS. Univariate and multivariate Cox proportional hazards analysis was used to evaluate associations with OS, CSS and RFS in patients with extreme obesity, among other known predictive variables. ResultsIn all, 100 patients (11.9%) with a BMI ≥ 40 kg/m 2 and 743 patients (88.1%) with a BMI < 40 kg/m 2 who were treated surgically for RCC were identified. Morbid obesity was not associated with an increased risk of blood transfusion (odds ratio [OR] 1, 95% confidence interval [CI] 0.587-1.70; P = 1.0). The median (interquartile range) length of hospital stay (LOS) was 4 (3-6) days. Morbid obesity was not associated with longer LOS (P = 0.26) or 30-day hospital readmission rates (P = 1.0). Major complications (Clavien ≥ 3a) were recorded in 67 patients (7.95%). BMI ≥ 40 kg/m 2 was not a predictor of major complications (OR 0.58, 95% CI 0.227-1.47; P = 0.251) or 90-day mortality (P = 0.4067). BMI ≥ 40 kg/m 2 was not associated with worse OS (P = 0.7), CSS (P = 0.2) or RFS (P = 0.5). BMI ≥ 35 kg/m 2 was also not associated with worse OS, CSS or RFS (P = 0.3, 0.1, 0.5, respectively). The 5-year OS rate was 68.9% for the entire cohort, including 69 and 70% for patients with BMI < 40 kg/ m 2 and BMI ≥ 40 kg/m 2 , respectively (P = 0.69). The 5-year CSS was 79.5% for the entire cohort, including 78.4 and 87.9% (P = 0.16) for patients with BMI < 40 kg/m 2 and BMI ≥ 40 kg/m 2 , respectively. The 5-year RFS rates for BMI < 40 kg/m 2 and BMI ≥ 40 kg/m 2 were 84.1 and 90.6%, respectively (P = 0.48). ConclusionsExtreme obesity is not associated with worse peri-operative or cancer outcomes after surgery for RCC. Surgery should remain a standard treatment option in well selected morbidly obese patients.

Association of body mass index with mortality and postoperative survival in renal cell cancer patients, a meta-analysis

“…Obesity, hypertension and smoking are known risk factors of RCC [ 4 – 10 ]. Increased BMI was reported to be associated with high RCC incidence [ 11 – 13 ] both in men and women [ 14 ], however, extreme obesity didn’t predict poor cancer outcomes after surgery in RCC patients [ 15 ], which indicated that the association between BMI and RCC prognosis is controversial. Therefore, we performed a meta-analysis to explore the relationship between BMI and RCC mortality as well as postoperative survival.…”

Differential effects of obesity on perioperative outcomes in renal cell carcinoma patients based on race and ethnicity and neighborhood-level socioeconomic status

“…However, unlike our study, previous studies focused on evaluating safety of minimally invasive surgical approach (laparoscopic or robotic partial nephrectomy) among obese patients and found no association between obesity and warm ischemia time ( 18 - 20 ). Obesity was associated with length of hospital study in a study of patients who underwent laparoscopic radical nephrectomy ( 24 ), but obesity was not associated with EBL or length of hospital stay in others studies of patient who underwent laparoscopic radical nephrectomy and studies including both nephrectomy types ( 22 , 23 , 41 , 42 ). In addition to potential differences in patients’ racial and ethnic and socioeconomic backgrounds, this study has several differences from previous studies.…”

Prognostic significance of promoter CpG island methylation of obesity‐related genes in patients with nonmetastatic renal cell carcinoma

“…Multiple studies, including a recent meta‐analysis, have suggested that having a higher BMI is associated with improved outcomes in patients with RCC . However, a recent study did not find extreme obesity to be an independent predictor of worse disease recurrence or survival in a multivariate analysis of patients with RCC who were surgically treated …”

“…7 However, a recent study did not find extreme obesity to be an independent predictor of worse disease recurrence or survival in a multivariate analysis of patients with RCC who were surgically treated. 43 Because epigenetic changes are more tissue-specific and the blood cell methylation profile may not indicate the epigenetic state of the tumor, one of the strengths of the current study is the ability to perform methylation analysis in RCC paired tissue samples, thereby demonstrating the important role of methylation in RCC tumorigenesis and clinical outcome. Another strength of this study is that we performed the methylation analysis using a quantitative evaluation of DNA methylation such as pyrosequencing, which may be more optimal for exploring the clinical significance of a given aberrant promoter methylation because qualitative evaluation may have overvalued low-level methylation, which has less clinical significance.…”