Purpose: The effect of bladder cancer histological subtypes other than transitional cell carcinoma (nonTCC) on clinical outcomes remains uncertain. We conducted a multi-institutional retrospective study of patients with bladder cancer treated with radical cystectomy to assess the impact of nonTCC histology on bladder cancer specific outcomes.
Materials and methods: A total of 955 consecutive patients underwent radical cystectomy with bilateral pelvic lymphadenectomy for bladder cancer at 3 academic institutions. TCC was present in the radical cystectomy specimen in 888 patients (93%). NonTCC histology was present in 67 patients (7%), including squamous cell carcinoma in 26, adenocarcinoma in 13, small cell carcinoma in 10 and other nonTCC subtypes (ie spindle cell carcinoma, carcinosarcoma and undifferentiated carcinoma) in 18. For patients alive at last followup median followup was 39 and 23 months for patients with TCC and nonTCC histologies, respectively. Bladder cancer specific progression and survival were assessed using Kaplan-Meier and multivariate Cox proportional hazards analyses.
Results: Bladder cancer specific progression and mortality did not differ significantly between patients with SCC and TCC histologies. Patients with nonTCC and nonSCC bladder cancer were at significantly increased risk for progression and death compared to patients with TCC or SCC (p <0.001). This association remained statistically significant in patients with organ confined disease (stage pT2 or lower) and patients with nonorgan confined disease (stage pT3 or higher) (p <0.001). In a multivariate analysis nonTCC and nonSCC histology was associated with an increased risk of bladder cancer progression and death (OR 2.272 and 2.585, respectively, p <0.001), even after adjusting for final pathological stage, lymph node status, lymphovascular invasion and neoadjuvant or adjuvant treatments.
Conclusions: NonTCC and nonSCC histological subtype is an independent predictor of bladder cancer progression and mortality in patients undergoing radical cystectomy for bladder cancer. Patients with bladder TCC and SCC share similar stage specific clinical outcomes.