Adjuvant chemotherapy after radical cystectomy for bladder cancer: a comparative study using inverse-probability-of-treatment weighting.

OBJECTIVES: The role of adjuvant chemotherapy (AC) after radical cystectomy for bladder cancer remains unclear. This study evaluated the benefits of cisplatin-based AC plus surgery versus surgery alone in patients with bladder cancer.
MATERIALS AND METHODS: The medical records of 746 patients who underwent radical cystectomy for bladder cancer were reviewed. The association between AC and survival was analyzed using Cox regression models. To reduce the impact of treatment selection bias and potential confounding in an observational study, significant differences in patient characteristics were rigorously adjusted using inverse-probability-of-treatment weighting (IPTW).
RESULTS: The cohort consisted of 746 patients (664 men and 82 women) of mean age 62.4 years and median follow-up of 64.3 months (range, 1-231.4 months). Of these patients, 176 (23.6%) received AC after cystectomy and 570 (76.4%) underwent cystectomy alone. Patients who received AC were significantly younger (60 vs. 63 years, p = 0.001) and significantly more likely to have high pathologic T stage (p = 0.001), lymph node metastasis (p = 0.001), high grade (p = 0.001), and lymphovascular invasion (p = 0.001) than patients who underwent cystectomy alone. Multivariable analysis showed a cancer-specific survival (CSS) benefit for AC [hazard ratio (HR) 0.56, 95% confidence interval (CI) 0.39-0.80, p = 0.002], as did low pathologic T stage, absence of lymph node metastasis, and absence of lymphovascular invasion. After IPTW adjustment for baseline characteristics, AC remained an independent predictor of CSS (HR 0.83, 95% CI 0.69-0.99, p = 0.043).
CONCLUSIONS: Cisplatin-based AC after radical cystectomy had survival benefits in patients with bladder cancer, even after IPTW adjustment for confounding variables.