Squamous Cell Carcinoma of the Bladder: Analysis of Treatments and Outcomes.

Abstract

Squamous cell carcinoma (SCC) of the bladder is a rare disease composing 2-5% of all bladder cancers. Currently, no consensus exists regarding treatment recommendations for this rare malignancy, although established regimens include various permutations of chemotherapy, radiation, laser treatments, immunotherapies, and surgeries, ranging from pelvic exenteration to local excision. The present study aims to analyze outcomes of the aforementioned treatments to guide clinical decision-making for patients with the disease. Patients with bladder SCC diagnosed between 2000 and 2018 were reviewed utilizing data from the Surveillance, Epidemiology, and End Results Registry (SEER) program. Data was analyzed using SPSS and Python. Examined variables included presence of metastases at diagnosis, surgery, radiotherapy, and chemotherapy reception. Five-year overall survival (OS) curves were analyzed using Kaplan-Meier probability stratified by treatment modality. A total of 5,635 patients with bladder SCC were identified; the most abundantly reported demographics were white race (86%), patient age > 70 years (61%), and male sex (63%). Median survival was 13 months and was significantly decreased in patients treated with chemotherapy or radiation (median survival of nine months or 12 months, respectively). Patients treated with radiation and surgery saw a decreased 10-year survival rate of about 10% if no chemotherapy was administered; this difference narrowed to about a 4% decrease in patients treated with chemotherapy. All radical surgical procedures (to include partial and total cystectomy, and total and posterior exenteration) resulted in a statistically significant increase in survival, except for patients that underwent radical cystectomy including anterior exenteration (p = 0.101). Patients that underwent surgery saw an increased median survival of 15 months. Heatmap analysis demonstrated a significant correlation between tumor size and distant metastases (r = 0.898). Preliminary unsupervised cluster analysis identified two distinct patient subgroups characterized most strongly by race and treatment modality used. Bladder SCC carries a high mortality burden, with a median survival time of 13 months after diagnosis. Based on this study's analysis, radical surgery may be the most effective treatment for this disease. This study also sets a precedent for future research, as more advanced machine learning methods (including cluster and binary tree analysis, as was done in this analysis) can be used to identify the most explanatory variables related to improved patient outcomes.