Analysis of the Clinicopathological Characteristics and Prognosis of Patients with Nonurothelial Bladder Cancer

Background: Due to the low incidence of nonurothelial bladder cancer (NUBC), there is limited evidence in the field of evidence-based medicine regarding treatment modalities for such diseases. The purpose of our study was to explore the clinicopathological characteristics and prognostic factors of NUBC.

Methods: We retrospectively analyzed the clinical data of 135 bladder squamous cell carcinoma (SqCC) and adenocarcinoma (AC) patients treated at the Second Hospital of Tianjin Medical University between October 2011 and February 2022, including 70 SqCC and 65 AC patients; We also analyzed 145 patients from the Surveillance, Epidemiology, and End Results (SEER) database from 2011 to 2020, including 108 SqCC and 37 AC patients. Clinicopathological characteristics and prognoses were compared between the SqCC and AC groups. Additionally, the Kaplan‒Meier method and log-rank tests were used to perform survival analysis, and the Cox proportional hazard model was applied to analyze clinical factors affecting prognosis.

Results: Comparisons of clinicopathological characteristics between the SqCC and AC groups revealed that age at diagnosis (p < 0.001, p < 0.001), tumor diameter (p < 0.001), tumor location (p = 0.002), and surgical approach (p < 0.001) were significantly different. Univariate and multivariate Cox regression analyses indicated that lymph node metastasis (p = 0.031), advanced pT stage (p < 0.001), and SqCC (p < 0.001) were independent risk factors affecting the prognosis of NUBC patients, and comparisons of clinicopathological characteristics between the SqCC and AC groups from the SEER database revealed that tumor diameter (p < 0.001), tumor location (p = 0.033), tumor number (p = 0.004), surgical approach (p = 0.005), and lymph node metastasis (p = 0.017) were statistically significant. Univariate and multivariate Cox regression analyses indicated that surgical approach (p = 0.003), lymph node metastasis (p = 0.005), age at diagnosis (p = 0.004), and SqCC (p = 0.028) were independent risk factors affecting the prognosis of NUBC patients.

Conclusions: NUBC is a rare pathological subtype of bladder cancer with a poor prognosis, and SqCC and AC are the most common histological subtypes of NUBC. Early diagnosis, radical cystectomy, and a focus on patients with lymph node metastasis, advanced pT stage, or SqCC may be helpful for ensuring the survival of NUBC patients.