TURKISH JOURNAL of ONCOLOGY Adult Rhabdomyosarcoma: Clinical Features and Radiotherapy Outcomes—The Turkish Oncology Group (TOG) Bone and Soft Tissue Sarcoma Study Group Received: September 04, 2018 Accepted: October 10, 2018 Online: October 26, 2018 Accessible online at: www.onkder.org This study has been conducted on behalf of Turkish Oncology Group (TOG) Bone and Soft Tissue Sarcoma Study Group and was presented as an oral presentation in 13 th National Radiation Oncology Congress at 30 th April 2018. Turk J Oncol 2018 doi: 10.5505/tjo.2018.1841 ORIGINAL ARTICLE Esra KORKMAZ KIRAKLI, 1 Ayça İRİBAŞ, 2 Arzu ERGEN, 3 Banu ATALAR, 4 Fulya AĞAOĞLU, 2 Fazilet ÖNDER DİNÇBAŞ, 3 Emin DARENDELİLER, 2 Yavuz ANACAK, 5 Serra KAMER 5 1 Department of Radiation Oncology, Dr. Suat Seren Chest Diseases and Surgery Training and Research Hospital, İzmir-Turkey 2 Department of Radiation Oncology, İstanbul University Oncology Institute, İstanbul-Turkey 3 Department of Radiation Oncology, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul-Turkey 4 Department of Radiation Oncology, Acıbadem University Faculty of Medicine, İstanbul-Turkey 5 Department of Radiation Oncology, Ege University Faculty of Medicine, İzmir-Turkey OBJECTIVE Although rhabdomyosarcoma (RMS) is the most frequent sof tissue sarcoma diagnosed in childhood, it represents only 2%–5% of adult sof tissue sarcomas. Te aim of the present study was to better under- stand the clinical characteristics, treatment approaches, and outcomes of patients with adult RMS who received radiotherapy (RT) as a component of their multidisciplinary management since there are scarce data on adult RMS due to its rarity. METHODS Te medical records of patients with adult RMS who were ≥18 years old and treated with RT between January 1995 and August 2016 in four diferent radiation centers were evaluated in terms of clinical characteristics, treatment, and follow-up data retrospectively. RESULTS Tere were 28 patients. Te median age at diagnosis was 28 (19–53) years. Te most common site of in- volvement was the head and neck (25%), and parameningeal region involvement was prominent (92%) among them. In general, unfavorable site of involvement was markedly higher than favorable ones (82% vs. 18%). Alveolar and pleomorphic subtypes compromised 75% of the cases. Fifeen patients had sur- gery, 26 chemotherapy, 10 radical intent of RT, 9 adjuvant, 3 preoperative, and 6 palliative. Te follow-up time was from 3 to 235 (median 18) months, disease-free survival was between 2 and 48 (median 12) months, and 5-year overall survival (OS) was 25% (median OS 20 (4–235) months). Tere were sig- nifcant diferences in terms of survival according to histopathological subtypes (p: 0.017), risk groups (p<0.001), Intergroup Rhabdomyosarcoma Study Group (IRSG) grouping and IRSG staging (p<0.001). CONCLUSION Adult RMS has unfavorable clinical presentation and worse outcome compared with pediatric RMS. Histopathological subtype and risk grouping to defne the prognosis used in pediatric cases also might be valid in adult RMS. Keywords: Adult rhabdomyosarcoma, Sof tissue sarcoma, Treatment, Outcomes. Copyright © 2018, Turkish Society for Radiation Oncology Dr. Esra KORKMAZ KIRAKLI Dr. Suat Seren Göğüs Hastalıkları ve Cerrrahisi Eğitim ve Araştırma Hastanesi, Radyasyon Onkolojisi, İzmir-Turkey E-mail: esrakirakli@gmail.com