Among patients with muscle-invasive bladder cancer (MIBC), those with squamous cell carcinoma have worse survival than those with urothelial carcinoma, according to a new study.
Unlike patients with urothelial carcinoma (UC), those with squamous cell carcinoma (SCC) treated with cystectomy do not derive a survival benefit from neoadjuvant chemotherapy (NAC).
Using the National Cancer Database, Justin T. Matulay, MD, of the University of Texas MD Anderson Cancer Center in Houston, and colleagues studied 394,979 patients with clinically localized MIBC, of whom 4,783 (1.2%) had SCC histology. The median overall survival (OS) from the time of bladder cancer diagnosis was significantly lower among patients with SCC than UC (9.6 vs 24.6 months), Dr Matulay’s team reported in Urologic Oncology. On multivariable analysis, SCC was independently associated with a significant 79% increased risk of death. The study also found that patients with SCC had worse survival compared with those who had UC when stratified by disease stage.
In the SCC group, the median OS was 25.4 months for patients who underwent radical cystectomy (RC) alone and 34 months for those who had RC plus NAC, a difference that was not statistically significant. Among the patients with UC, RC plus NAC was associated with significantly longer OS compared with RC alone (63.4 vs 39.2 months). On multivariable analysis, NAC was independently associated with a significant 17% decreased risk of death in the UC group, but not in the patients with SCC, according to the investigators.
“There is no clear explanation for why SCC exhibits a more aggressive phenotype than UC, but we may soon be able to look toward genetic information to help shed light,” the authors wrote. “By clinically demonstrating a more aggressive course for SCC, studies such as ours suggest that there is likely an underlying genetic difference of this rare subtype worth exploring at the molecular level.”
Matulay JT, Woldu SL, Lim A, et al. The impact of squamous histology on survival in patients with muscle-invasive bladder cancer. Urol Oncol. 2019; published online ahead of print.