title: The role of radiotherapy for thymic carcinoma.
abstract: OBJECTIVE
  The aim of this study is to evaluate retrospectively the role of radiotherapy for thymic carcinoma.
  
  
  METHODS
  Between 1973 and 1998, 14 patients with thymic carcinoma were treated at Gunma Prefectural Cancer Center. Two patients who had hematogenous metastasis were excluded from this study, therefore 12 patients were analyzed. The Masaoka staging system was used; four patients were diagnosed with stage III disease and eight patients with stage IV disease. The pathological subtype according to the World Health Organization histological criteria for thymic tumors was squamous cell carcinoma (low-grade histology) in six cases and undifferentiated carcinoma (high-grade histology) in six. Ten patients underwent thoracotomy, and two patients underwent excisional biopsy without thoracotomy. Ten patients (83%) received radiotherapy as a curative intent, and the median dose was 60 Gy. Systemic chemotherapy was administered to four patients (33%), and the majority (75%) of the regimens contained cisplatin.
  
  
  RESULTS
  The 3-year overall survival rate was 25%. Histological subtype (low-grade versus high-grade), surgical resection (complete versus incomplete), radiotherapy and chemotherapy were evaluated as prognostic factors in a univariate analysis. Low-grade histology and complete resection were good prognostic factors, although these were not statistically significant. Patients who received radiotherapy had a better outcome than those who did not. The major sites of recurrence were the pleura and pericardium. Recurrence within the radiation field was observed in one of seven patients in whom failure patterns could be evaluated.
  
  
  CONCLUSIONS
  Complete resection is mandatory if possible. Radiotherapy plays an important role in treating thymic carcinoma in terms of reducing local recurrence and prolonging survival time. Establishment of an innovative treatment protocol that includes chemotherapy is necessary to control intrathoracic relapse and distant metastasis.
authors.affiliation: Department of Radiation Oncology, Gunma Prefectural Cancer Center, Ohta, Gunma, Japan. tnonaka@med.gunma-u.ac.jp
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nonaka
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tamaki
authors.forename: Keiko
authors.initials: K
authors.lastname: Higuchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Katoh
authors.forename: Masumi
authors.initials: M
authors.lastname: Nakahashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Horikoshi
authors.forename: Kenro
authors.initials: K
authors.lastname: Takahashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Minato
authors.forename: Shiro
authors.initials: S
authors.lastname: Sugihara
authors.forename: Masaru
authors.initials: M
authors.lastname: Kojima
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002277:Carcinoma / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D015996:Survival Rate; D013908:Thoracotomy; D013953:Thymus Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D016896:Treatment Outcome