Clinical features and prognosis of small cell carcinoma of the bladder: a single center retrospective analysis.

BACKGROUND

Small cell carcinoma of the bladder (SCCB) is a rare and aggressive subtype, usually diagnosed at advanced stages. Due to its rarity, the clinical features, prognostic factors, and treatment strategies are not well defined, and data on long-term outcomes are limited. This study aims to analyze the clinical characteristics, treatment options, and prognostic factors of SCCB to enhance clinical understanding and guide practice.

METHODS

A retrospective analysis of 41 SCCB cases treated at Changhai Hospital between 2006 and 2023 was conducted. Clinical, pathological, and treatment data were collected. The median follow-up duration was calculated as 41.0 months [95% confidence interval (CI): 31.3-50.7] using the reverse Kaplan-Meier method. Overall survival (OS) rates were estimated using the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were used to identify prognostic factors.

RESULTS

The median age was 71 years (range, 41-89 years). Pure SCCB accounted for 56.1% of cases, and 48.78% of tumors were located on the lateral bladder wall. Tumors ≥4 cm were found in 56.10% of cases. According to the tumor-node-metastasis (TNM) classification, 63.41% of patients underwent radical cystectomy, and 34.14% had lymph node or distant metastasis. None of the patients received neoadjuvant chemotherapy (NACT), while 41.03% underwent adjuvant chemotherapy post-surgery. The median OS was 30 months, with 1- and 3-year OS rates of 74.8% and 41.4%, respectively. Univariate analysis showed that T stage (P=0.002), lymph node metastasis (P<0.001), and distant metastasis (P<0.001) were associated with poor prognosis. Multivariate analysis confirmed T stage (P=0.04) and distant metastasis (P<0.001) as independent prognostic factors.

CONCLUSIONS

SCCB is often diagnosed at a late stage with gross hematuria as the most common symptom, Neoadjuvant therapy and immunotherapy can extend OS. T stage and distant metastasis are critical prognostic factors. Early diagnosis and intervention are crucial for improving outcomes.