Background: Adults with rhabdomyosarcoma (RMS) have a worse clinical outcome compared to pediatric cases. In the present study, the failure pattern and clinical outcome of adult patients with RMS who received multimodality treatment at our Institution was assessed. Patients and Methods: Data were retrospectively recorded and analyzed from 20 adult patients, aged 19 years or more, who were treated for RMS at our Institution between 2004 and 2015. Disease-free (DFS) and overall (OS) survival after starting treatment were calculated using the Kaplan-Meier method. The relationship of these outcome measures with the following variables was then assessed: Primary site, tumor stage, lymph node involvement, histological subtype, radiotherapy (RT), and duration of chemotherapy. Results: Sixteen patients had localized RMS, and four had metastatic disease. For the whole patient cohort, the 3-year DFS and OS rates were 20%, and 45%, respectively. Patients with alveolar histological subtype had a better 3-year OS than those with other subtypes (p=0.038). The median OS rates for those with localized and metastatic disease were 53.2 (95% confidence interval(CI)=14.7-91.8) months, and 21.7 (95% CI=0-45.7) months, respectively (p=0.047). In patients with localized RMS, those who received RT (n=13) had a better median DFS (24.6 versus 6.0 months, p=0.009) and OS (53.2 versus 11.4 months, p=0.009) than those who did not (n=3).For patients receiving RT, concurrent chemotherapy with vincristine and cyclophosphamide (n=11) was associated with better 3-year DFS (36.4% versus 0%, p<0.001) and OS (81.8% versus 0%, p<0.001) compared with RT alone (n=2). Administration of chemotherapy for more than 19 weeks significantly correlated with better 3-year DFS (44% versus 0%, p=0.001) and OS (53.3% versus 0%, p<0.001) in those with localized RMS. Conclusion: In addition to staging and histological subtype, our results indicate that concurrent chemoradiotherapy and longer duration of chemotherapy were associated with significantly improved DFS and OS in adult patients with localized RMS.Rhabdomyosarcoma (RMS) is the most common soft-tissue malignancy, accounting for 4-5% of cancer cases in children (1). In Taiwan, soft-tissue sarcoma accounted for approximately 40% of all pediatric cancers diagnosed between 1996 and 2010, with RMS comprising 6% of all pediatric soft-tissue sarcomas (2). RMS is far less common in adults (2). Although most cases occur in children younger than 10 years, adult RMS still accounted for 41% of all RMS cases in the Surveillance, Epidemiology and End Results (SEER) database between 1973 and 2005 (3). Pediatric patients with RMS are typically treated within clinical studies or by standard protocols. In the United States, the Intergroup Rhabdomyosarcoma Study Group (IRSG; now the Children's Oncology Group Soft-Tissue Sarcoma Committee) organized a series of studies incorporating multimodality treatment (chemotherapy, surgery, and radiotherapy) to treat pediatric RMS, and the 5-year overall survival (OS) after treatment cle...