Preoperative metastatic status, level of thrombus and body mass index predict overall survival in patients undergoing nephrectomy and inferior vena cava thrombectomy

UNLABELLED: Study Type - Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Little is known about the prognostic impact of body mass index (BMI) and obesity on patients with locally advanced kidney cancer. Previous studies suggest that clinical/pathological stage, the proximal extent of the tumour thrombus, direct vascular wall invasion, and preoperative performance status may all constitute important prognostic factors within this patient population. The present study shows that a patient's metastatic status, higher level of tumour thrombus, and lower BMI all constitute adverse predictors of overall survival in patients who have RCC with inferior vena cava tumour thrombus. OBJECTIVE: • To determine which clinical variables, including body mass index (BMI), predict overall survival (OS) after nephrectomy with inferior vena cava (IVC) thrombectomy for renal cell carcinoma (RCC) with tumour thrombus. PATIENTS AND METHODS: • After institutional review board approval, a retrospective analysis of all patients (N= 100) undergoing nephrectomy and IVC thrombectomy for RCC from 1989 to 2010 were reviewed. One patient was excluded owing to missing clinical information leaving 99 patients in the study cohort. • Patients were placed into one of two subgroups, based on their preoperative BMI (BMI ≤30 kg/m(2) or BMI >30 kg/m(2) ). • Complications, blood loss, level of tumour thrombus, side of tumour and follow-up data were tabulated. RESULTS: • Fifty-six patients had a BMI ≤30 kg/m(2) and 43 patients had a BMI >30 kg/m(2) . Intraoperative complications occurred in 14% of those with BMI >30 kg/m(2) and 5.4% of those with a BMI ≤30 kg/m(2) (P= 0.171). • On multivariate analysis, a higher thrombus level (III/IV vs I/II) and the presence of metastatic disease at time of diagnosis was associated with a worse OS (P= 0.041 and P < 0.001, respectively). • The subgroup with a higher preoperative BMI had a significantly better OS (hazard ratio 0.42; 95% confidence interval 0.22-0.80, P= 0.009). • Similarly, our Kaplan-Meier survival analysis showed an improved OS in the patient cohort with a BMI >30 kg/m(2) (P= 0.016). CONCLUSION: • Important predictors of outcome in patients undergoing nephrectomy with IVC thrombectomy for RCC with tumour thrombus include preoperative BMI, level of IVC tumour thrombus, and metastatic status at time of surgery.