Body mass index as independent predictor of overall survival in patients with advanced renal cell carcinoma at start of systemic treatment-Analyses from the German clinical RCC-Registry

Objectives: A high body mass index (BMI) is associated with an increased risk for developing renal cell carcinoma (RCC), a higher complication rate after surgery, and a postoperative decline in renal function after nephrectomy. In contrast, a high preoperative BMI has been associated with increased survival in patients with localized RCC. We examined the prognostic impact of the BMI in patients treated for metastatic RCC (mRCC) in daily routine practice in Germany.

Patients and methods: The ongoing prospective, multicenter German clinical cohort study on mRCC (RCC-Registry) has recruited patients from more than 110 oncology/urology outpatient centers and hospitals at initiation of systemic first-line treatment. Data on patients' demographics, treatment, and outcome in routine practice, so called "real world data", have been collected. For this analysis, 606 patients were stratified into a low (BMI < 24), medium (24 < BMI < 28), and high (BMI > 28) BMI group. The influence of the BMI on the overall survival (OS) was analyzed using a multivariate Cox proportional hazards model.

Results: Median OS was 24.5 (95% confidence interval [CI], 19.3-28.5), 17.9 (95% CI, 15.3-20.8) and 10.9 (95% CI, 7.3-13.4) months in the high, medium, and low BMI patient group, respectively. A significant correlation of BMI with OS, independent of other factors, was found (low vs. high BMI: hazard ratio (HR): 1.94, 95% CI, 1.48-2.54; medium vs. high BMI: HR: 1.40, 95% CI, 1.10-1.78). Memorial Sloan Kettering Cancer Center risk factors were independently correlated with shorter OS.

Conclusions: Our analysis showed a significant and independent correlation of a high BMI with longer OS in a prospective German cohort of mRCC routine patients starting first-line systemic treatment.