Treatment Outcome and Predictors of Survival in Thai Adult Rhabdomyosarcoma Cases

Background: Adult rhabdomyosarcoma (RMS) is a rare and aggressive disease with limited data compared with pediatric RMS. The goal of this study was to determine the treatment outcome and identify factors related to survival outcome in Thailand. Materials and Methods: Adult patients (${\geq}15$ years old) with the pathological diagnosis of RMS between 1985 and 2010 were reviewed. The data were retrospectively reviewed from the pathological results and medical records from Srinagarind Hospital, Khon Kaen University. Results: A total of 34 patients were identified in the study. The median age at diagnosis was 35.5 years and the most common primary sites were extremity and the head and neck region. The incidence of pleomorphic RMS increased with age and none was found in those aged younger than 20 years old. The median survival time was 9.33 months (95%CI: 5.6-13.1). The 1- and 5- year survival rates were 38.2% (22.3-54.0) and 20.6% (9.1-35.3). On multivariate analysis, age and size of tumor did not predict better outcome while chemotherapy and surgery were significantly associated with longer survival. Conclusions: Outcome of adult RMS was poor. Surgery and chemotherapy are strongly associated with better prognosis and multimodality treatment should be incorporated in the clinic.