Comparative Outcomes of Pure Squamous Cell Carcinoma and Urothelial Carcinoma With Squamous Differentiation in Patients Treated With Radical Cystectomy

Purpose: We compared clinical outcomes, and identified predictors of cancer specific and overall survival after radical cystectomy in patients with urothelial carcinoma with squamous differentiation and those with pure squamous cell carcinoma. Materials and Methods: We reviewed data on 2,031 patients treated with radical cystectomy and pelvic lymph node dissection at a single high volume referral center. Of these patients 78 had squamous cell carcinoma and 67 had squamous differentiation. Survival estimates by histological subtype were described using Kaplan-Meier methods. Within histological subtypes pathological stage, nodal invasion, soft tissue margins, age and gender were evaluated as predictors of cancer specific survival and overall survival using univariate Cox regression. Results: Median followup was 44 months. Of 104 patient deaths 60 died of their disease. We did not find a statistically significant difference between survival curves of patients with squamous cell carcinoma and squamous differentiation (log rank overall survival p = 0.6, cancer specific survival p = 0.17). Positive soft tissue margins were associated with worse cancer specific survival (HR 6.92, 95% CI 2.98-16.10, p <= 0.0005) and overall survival (HR 3.68, 95% CI 1.84-7.35, p <= 0.0005) in patients with pure squamous cell carcinoma. Among patients with squamous differentiation, pelvic lymphadenopathy was associated with decreased overall survival (HR 2.52, 95% CI 1.33-4.77, p = 0.004) and cancer specific survival (HR 3.23, 95% CI 1.57-6.67, p = 0.002). Conclusions: There appears to be no evidence of a difference in cancer specific survival or overall survival between patients with squamous cell carcinoma and those with squamous differentiation treated with radical cystectomy and pelvic lymph node dissection. Patients with squamous differentiation and tumor metastases to pelvic lymph nodes should be followed more closely, and adjuvant treatment should be considered to improve survival. Wide surgical resection is critical to achieve local tumor control and improve survival in patients with squamous cell carcinoma.