Supplementary Material for: Leiomyosarcoma of the Urinary Bladder in Adult Patients: A Systematic Review of the Literature and Meta-Analysis

<b><i>Purpose:</i></b> Leiomyosarcoma of the urinary bladder is exceedingly rare. Most clinicians come across only a few cases during their career, and information regarding treatment and outcome is scattered in the scientific literature. Interested clinicians and patients have to undertake troublesome search for treatment and outcome information. <b><i>Material and methods:</i></b> We performed a systematic review of the literature using the PubMed and Web of Science databases and included all identified cases published in English language between 1970 and June 2018 into a meta-analysis. Prior to the literature search, key questions were formulated and with the data obtained, answers to these questions should be derived. <b><i>Results:</i></b> We analyzed clinical data of 210 cases of urinary bladder leiomyosarcoma revealed by this review and seen in our institution. The mean age of patients was 52 years. The majority (75%) of the tumors was classified as high-grade sarcomas. We found no report of a prior radiation therapy to the pelvic organs, but some authors suggested an association between cyclophosphamide treatment and the development of bladder leiomyosarcoma, especially in patients with retinoblastoma. For the whole sample, we determined 5- and 10-year cancer-specific cumulative mortality rates of 38 and 50%. Patients with high-grade sarcomas had a trend toward a higher mortality compared with low-grade tumors (<i>p</i> = 0.0280). The most promising treatment option seems to be surgery (radical or partial cystectomy) with negative resection margins, possibly supplemented by chemotherapy or radiation. <b><i>Conclusion:</i></b> About half of patients with bladder leiomyosarcoma survived on the long run. Low-grade tumors may have a better outcome with, nevertheless, countable long-term mortality. For better assessment of that rare bladder tumor, its best treatment options, and the influence of neoadjuvant or adjuvant therapies on the outcome of patients, a larger series with long-term survival data is required.