Bimodal pattern of the impact of body mass index on cancer-specific survival of upper urinary tract urothelial carcinoma patients.

AIM: To clarify how body mass index (BMI) affects the risk of death from upper urinary tract urothelial carcinoma (UUTUC) we investigated the impact of BMI on UUTUC using a Japanese multicenter database. PATIENTS AND METHODS: Between January 1995 and December 2010, 1,329 patients with upper urinary tract tumors were treated in 13 institutions in Japan. From this group, a cohort of 1,014 patients treated with radical nephroureterectomy was retrospectively reviewed. BMI was categorized into the following three groups: BMI <22.5, BMI 22.5 to <25 and BMI ≥ 25. The association between each group and cancer-specific survival (CSS) was analyzed using Cox proportional hazards regression models. RESULTS: The median BMI was 22.4 kg/m(2) (interquartile range, 20.5-24.8). Out of all patients, 213 (21%) died of UUTUC. Hazard ratios of the BMI ≥ 25 and the BMI <22.5 group were 1.76 and 1.66, respectively. CONCLUSION: Both higher and lower BMI affect the prognosis of UUTUC treated with radical nephroureterectomy.