Recurrence and treatment of adult primary nonmetastatic bladder rhabdomyosarcoma: A systematic review

Introduction: While survival for pediatric bladder rhabdomyosarcoma (RMS) has recently improved with risk-based multimodality treatment protocols, survival for adult bladder RMS remains to be poor. Survival is poor likely because adult bladder RMS is rare, understudied, and consequently lacking in high-level evidence to inform standardization of treatment. In addition, adult bladder RMS exhibits high rates of recurrence. The purpose of this systematic review is to determine associations between patient clinicopathologic factors and recurrence for adult primary bladder RMS, as well as to provide an updated survey of the various treatments employed for this disease in adults.

Material and methods: Studies involving adult primary bladder RMS were acquired from MEDLINE (OVID), Scopus, and Cochrane Central Register of Controlled Trials from 1947 to 2018. Cases with no metastatic disease at diagnosis and at least 6 months follow-up were included. Multivariable Cox-regression hazard analysis was utilized to determine associations of age, sex, histology, and TNM stage with recurrence. Kaplan-Meier analysis and log-rank testing was used to calculate overall survival (OS) for patients who underwent surgical treatment only, and to evaluate differences in survival between radical cystectomy and partial cystectomy.

Results: 20 articles were selected for the review, and 22 cases were obtained. The mean age of the patients was 55.7 ± 18.4 (range = 28-83). With a mean follow-up time of 21.4 ± 18.6 months, 36.4% of the patients experienced disease recurrence. Recurrence was not associated with age, sex, histology, or stage (p = 0.366, p = 0.754, p = 0.889, and p = 0.590, respectively). Most patients underwent surgery only as their initial therapy (n = 12), while the remaining had chemotherapy, radiation, or some combination of these therapies (including surgery). The median OS of patients who underwent surgery only was 21.0 months (95% CI: 0.0-44.6 months). Among these patients, no difference in OS between radical cystectomy and partial cystectomy was found (p = 0.841).

Conclusion: Adult bladder RMS is a rare, lethal tumor with a high proclivity for recurrence. No association between age, sex, histology, or stage and recurrence was found. Radical cystectomy is not superior to partial cystectomy in terms of survival, suggesting a role for bladder preservation in select patients. Our study is the first to provide a comprehensive summary of the various treatments employed with clinical outcomes for adult primary bladder RMS.