The effect of chemotherapy in sarcomatoid bladder cancer patients treated with radical cystectomy

Data about the role of chemotherapy in sarcomatoid bladder cancer (SBC) are limited. We addressed the effect of chemotherapy in non-metastatic SBC patients treated with radical cystectomy (RC).

Using the Surveillance, Epidemiology, and End Results database (2001-2018), we identified 331 patients with non-metastatic muscle-invasive or higher SBC (T_2-4N_0-3M₀). Kaplan-Meier plots and Cox regression models tested cancer-specific mortality (CSM ). Sample size and power analyses tested for power limitations.

Of 331 SBC patients, 129 (38.9%) were exposed to chemotherapy. The rate of organ-confined stage (T₂N₀M₀) was 33% in both chemotherapy-exposed and chemotherapy-naive patients. In the overall cohort, median CSM-free survival was 84 months (interquartile range [IQR] 21-NA) vs. 26 months (IQR 17-84) in chemotherapy exposed vs. chemotherapy-naive patients, respectively. In multivariable Cox regression models, chemotherapy was associated with lower CSM, without reaching statistical significance (hazard ratio [HR ] 0.72, confidence interval [CI] 0.51-1.01, p=0.054). In subgroup analyses, chemotherapy exposure in organ-confined (n=110) vs. non-organ-confined (n=221) patients resulted in a HR of 0.51 (p=0.12) vs. 0.77 (p=0.17), respectively. Power analyses, based on two-sided α=0.05, revealed values of 52%, 14%, and 43% in the entire population, organ-confined, and nonorgan-confined subgroups, respectively.

In non-metastatic SBC treated with RC, the association between chemotherapy and lower CSM is particularly strong in organ-confined stage. A substantially larger cohort would be required to confirm the statistical significance of the recorded protective effect of chemotherapy.