Overweight status predicts improved overall survival after radical nephroureterectomy for upper tract urothelial carcinoma.

INTRODUCTION

Upper urinary tract urothelial carcinoma (UTUC) is a rare malignancy, particularly in the ureter, and is associated with high rates of recurrence and metastasis. Although body mass index (BMI) has been associated with prognosis in multiple cancer types, its role as a predictive factor in UTUC is still debated. This study aimed to investigate how BMI influences survival outcomes in patients with UTUC treated with radical nephroureterectomy (RNU).

METHODS

This multi-center retrospective analysis by the Taiwan UTUC Collaboration Group involved 2503 patients who underwent treatment across 19 hospitals from 1988 to 2022. Patients were categorized into normal (18.5 ≤ BMI < 24), overweight (24 ≤ BMI < 27), and obese (BMI ≥ 27) groups. Demographic, clinical, and pathological data were analyzed. Overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS), and intravesical recurrence-free survival (IVRFS) were assessed using Kaplan-Meier analysis and Cox proportional hazards models.

RESULTS

The median follow-up period was 44.2 months. In multivariable analysis, overweight patients demonstrated significantly better OS compared with normal-weight patients (p = 0.033), and the obesity group showed a favorable, though not statistically significant, trend toward better OS. However, BMI was not an independent predictor of CSS, DFS, or IVRFS. Independent predictors of worse outcomes included older age, end-stage renal disease, ureteral tumor location, tumor size ≥3 cm, and high-grade urothelial carcinoma. Tumor stage and grade were comparable across BMI groups.

CONCLUSIONS

Overweight status was associated with better OS in patients with UTUC treated with RNU, while BMI had no significant impact on CSS, DFS, or IVRFS. These findings suggest a potential protective effect of higher BMI on OS, warranting further investigation in prospective studies. However, BMI alone should not guide clinical decisions and may instead reflect broader patient health characteristics.