SUO 2017: Comparing Effective Treatment Strategies for Squamous Cell Carcinoma of the Bladder

Washington, DC ( Dr. Stensland and colleagues presented their work assessing comparative effectiveness of treatment strategies for squamous cell carcinoma of the bladder. Because treatment recommendations for muscle invasive bladder cancer (MIBC) are primarily based on urothelial carcinoma histology, the effectiveness of treatment strategies for variant histologies has been understudied. The objective of this study was to assess the effectiveness of primary treatment strategies for squamous cell carcinoma. 

The authors identified 828 patients in the National Cancer Database (NCDB) with localized MIBC (T2-3N0M0) with squamous cell histology. Treatment variables assessed included surgery (radical cystectomy, RC), chemotherapy (single or multi-agent), and external beam radiation. Neoadjuvant chemotherapy was defined as receipt of chemotherapy within 180 days pre-RC, while adjuvant chemotherapy was defined as receipt of chemotherapy within 180 post-RC. Patients with missing survival time or who received no treatment were excluded from this study. A multinomial propensity score method was used to create treatment weights which were then applied in weighted Cox proportional hazards models to assess the comparative effectiveness of treatments on overall survival (OS), adjusted for age, TNM clinical stage, Charlson comorbidity index, and gender. There were 639 (77%) clinical T2 and 189 (23%) clinical T3 cases. The majority of patients received RC alone (n=465, 56%), followed by chemoradiation (n=102, 12%), radiation alone (n=88, 11%), chemotherapy alone (n=72, 8.7%), neoadjuvant chemotherapy + RC (n=53, 6.4%), and RC + adjuvant chemotherapy (n=48, 5.7%). Non-surgical treatments were all associated with significantly worse outcomes (vs RC: chemotherapy alone HR 2.16, 95%CI 1.54-3.02; radiation alone HR 2.81, 95%CI 1.79-4.42). The addition of neoadjuvant (HR 1.32, 95%CI 0.93-1.89) or adjuvant chemotherapy (HR 0.74, 95%CI 0.47-1.17) did not significantly improve OS in this population. Furthermore, there were no differences in OS for patients with T2 and T3 disease. A limitation of the NCDB is the inability to assess disease-specific outcomes.

In conclusion, RC is associated with better survival for patients with squamous cell muscle invasive bladder cancer and should be considered an upfront treatment in this population. While there was a non-statistically significant association of adjuvant chemotherapy on survival, which patients benefit from adjuvant therapy warrants further evaluation.

Presented by: Kristian Stensland, Lahey Hospital and Medical Center, Burlington, MA
Co-Authors: Jared Schober, Harras Zaid, David Canes, Matt Galsky, Alireza Moinzadeh

Written by: Zachary Klaassen, MD, Society of Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC