Introduction

Squamous cell carcinoma of the bladder (SCC) is the second most common histological subtype of bladder cancer after urothelial carcinoma (UC). We sought to compare clinical outcome and differences in staging between both subtypes.

Methods

In our institution, follow-up data of 714 patients with pure UC and 39 patients with pure SCC undergoing radical cystectomy (RC) between 2004 and 2015 is available. First, cancer-specific survival (CSS) was analyzed among both subtypes. As a second step, staging, grading and histological subtypes were compared in a multivariate Cox-regression analysis. Lastly, distribution of advanced disease (pT3-4, pN+, M1, G3) between UC and SCC was assessed.

Results

CSS of patients with SCC is significant worse compared to UC in a univariate analysis (p=0.032). In a multivariate analysis only T score pT<3 vs. pT3-4 (hazard ratio [HR] = 3.2; 95% CI: 2.3-4.5, p<0.001), N score pN0 vs. pN+ (HR = 2.0; 95% CI: 1.5-2.6, p<0.001) and M score M0 vs. M1 (HR = 2.8; 95% CI: 2.0-4.0 p<0.001) were significantly associated with CSS. There was no significant impact of grading G1-2 vs. G3 (HR = 1.2; 95% CI: 0.7-1.9 p<0.517) and histological subtype UC vs. SCC (HR = 1.4; 95% CI: 0.8-2.5 p<0.176) on CSS. Compared to UC, SCC presents with pT3-4 nearly twice as often (44% vs. 85%, p<0.001). High grade (G3) is more common in UC compared to SCC (89% vs. 64%, p<0.001). There is no significant difference between N score (UC 28% vs. SCC 29%, p=0.808) and M score (UC 11% vs. SCC 5%, p=0.262) between both bladder cancer subtypes.

Conclusions

Compared to UC, patients with SCC have a decreased CSS. The reason for this phenomenon may not lie within the histological subtype itself, but rather in a more progressive disease at the point of RC. This is reflected by the prevalence of pT3-4 stage, which is nearly twice as often in SCC compared to UC. Future studies concentrating on early detection of SCC should be encouraged in order to improve CSS of the latter bladder cancer entity.

Funding

none