Squamous or Glandular Differentiation Predicts Poor Prognosis in pT1 Urothelial Carcinoma

Background: The aim of this study was to evaluate the prognosis of patients with T1N0M0 urothelial carcinoma with squamous differentiation (UCSD) or glandular differentiation (UCGD) because it has not been determined whether these variant histologies behave more aggressively than pure urothelial carcinoma (PUC).

Patients and methods: Ninety-nine patients diagnosed with pT1N0M0 bladder cancer and treated conservatively with transurethral resection of bladder tumor at Kanazawa University Hospital between 2007 and 2019 were included in this study. The overall survival, cancer-specific survival (CSS), and recurrence-free survival of the variant histology and PUC groups were evaluated and compared.

Results: The variant histology group had significantly lower overall survival (p=0.006) and CSS (p=0.0095) than the PUC group did. Variant histology was found to be an independent prognostic factor in univariate and multivariate analyses for overall survival and CSS. On the other hand, no significant difference in progression-free survival was observed between the two groups (p=0.439). However, the variant histology group had significantly lower overall survival (p=0.004) and CSS (p=0.004) after progression.

Conclusion: The prognosis for patients with pT1 bladder cancer with UCSD or UCGD treated conservatively with transurethral resection of bladder tumor was poor. Considering the worse prognosis of these patients after stage progression, early radical cystectomy could be recommended.