Influence of body mass index on oncological outcomes in patients with upper urinary tract urothelial carcinoma treated with radical nephroureterectomy.

OBJECTIVE

To investigate the association between body mass index and oncological outcomes in Chinese patients who had undergone radical nephroureterectomy for upper urinary tract urothelial carcinoma.

METHODS

Between August 1998 and October 2009, 236 consecutive Chinese patients underwent radical nephroureterectomy for upper urinary tract urothelial carcinoma at Sun Yat-sen University Cancer Center (Guangzhou, China). Body mass index data were available for 230 (97.5%) of these patients. All 230 patients were classified into three groups according to the body mass index criteria for Asians, issued by the Asia Cohort Consortium: underweight, body mass index <18.5 kg/m(2) (n = 21, 9.1%); normal weight, body mass index ≥18.5 and <25 kg/m(2) (n = 151, 65.7%); and obesity, body mass index ≥25 kg/m(2), (n = 58, 25.2%). Spearman's rank correlation, Kaplan-Meier plots and Cox proportional hazards regression model were used to analyze the data.

RESULTS

Being underweight was significantly associated with lymph node metastasis (P = 0.017) and Eastern Cooperative Oncology Group performance status (P = 0.003). Univariate analysis showed recurrence-free survival and cancer-specific survival were significantly worse in underweight patients than in patients with normal weight or obese patients. After adjustments for other clinicopathological variables, multivariate analysis confirmed that recurrence-free survival and cancer-specific survival were significantly worse in underweight patients than in patients with normal weight or obese patients (recurrence-free survival P = 0.014, cancer-specific survival P = 0.015).

CONCLUSIONS

Preoperative underweight is an independent predictor of unfavorable recurrence-free survival and cancer-specific survival in Chinese patients with upper urinary tract urothelial carcinoma treated by radical nephroureterectomy, whereas obesity is associated with superior recurrence-free survival and cancer-specific survival. Further studies, including a multi-institutional, prospective, Asian cohort study, are required to confirm these findings.