Comprehensive analysis of oncological outcomes of radical cystectomy for non-muscle invasive bladder cancer

Owing to the rarity of radical cystectomy (RC) for non-muscle-invasive bladder cancer (NMIBC), information regarding oncological outcomes is limited. The aim was to conduct a comprehensive analysis of risk factors and survival outcomes following RC. This retrospective study included 435 patients who underwent RC for clinically diagnosed NMIBC at multiple institutions in Japan. The 5-year cancer-specific survival (CSS) rates were 97.4% for cTa, 93.3% for cTis, and 85.4% for cT1, respectively. Among 351 patients with cTa and cT1 disease, multivariable Cox proportional hazards analyses identified upstaging to ≥pT2 or pN+ disease as the most impactful risk factor associated with cancer-specific mortality (hazard ratio = 6.53; p < 0.001). Neither neoadjuvant chemotherapy nor lymph node dissection (LND) exhibited a survival benefit in terms of CSS in this cohort; however, LND was occasionally indicative of pN+ disease, suggesting potential diagnostic value. The multivariable logistic regression analysis of preoperative variables identified tumour size (≥ 3 cm) as the lone risk factor associated with upstaging (odds ratio = 1.90; p = 0.03). In the sensitivity analyses, tumour size ≥ 3 cm still trended toward an increased upstaging risk, without a statistically significant association. Although the prediction of upstaging remains highly challenging, RC should not be delayed when clinically indicated, even for patients diagnosed with NMIBC, particularly in those with large tumours.