title: Survival Impact of Adjuvant Radiation Therapy in Masaoka Stage II to IV Thymomas: A Systematic Review and Meta-analysis.
abstract: OBJECTIVE
  To evaluate the survival impact of postoperative radiation therapy (PORT) in stage II to IV thymomas, using systematic review and meta-analysis.
  
  
  METHODS
  A database search was conducted with EMBASE, PubMed, Web of Science, Cochrane Library, and Ovid from inception to August 2015. Thymic carcinomas were excluded, and studies comparing overall survival (OS) with and without PORT in thymomas were included. The hazard ratios (HRs) of OS were extracted, and a random-effects model was used in the pooled analysis.
  
  
  RESULTS
  Seven retrospective series with a total of 1724 patients were included and analyzed. Almost all of the patients underwent macroscopically complete resection, and thymoma histology was confirmed by the World Health Organization criteria. In the overall analysis of stage II to IV thymomas, OS was not altered with the receipt of PORT (HR 0.79, 95% confidence interval [CI] 0.58-1.08). Although PORT was not associated with survival difference in Masaoka stage II disease (HR 1.45, 95% CI 0.83-2.55), improved OS was observed with the addition of PORT in the discrete pooled analysis of stage III to IV (HR 0.63, 95% CI 0.40-0.99). Significant heterogeneity and publication bias were not found in the analyses.
  
  
  CONCLUSIONS
  From the present meta-analysis of sole primary thymomas, we suggest the potential OS benefit of PORT in locally advanced tumors with macroscopically complete resection, but not in stage II disease. Further investigations with sufficient survival data are needed to establish detailed treatment indications.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Lim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eunji
authors.initials: E
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: khjae@snu.ac.kr.
authors.forename: Hak Jae
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hong-Gyun
authors.initials: HG
authors.lastname: Wu
authors.affiliation: Department of Radiation Oncology, Dalian Medical University, Liaoning, China; Department of Radiation Oncology, Fudan University Cancer Hospital, Shanghai, China.
authors.forename: Jinchun
authors.initials: J
authors.lastname: Yan
authors.affiliation: The Wistar Institute, Philadelphia, Pennsylvania.
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Radiation Oncology, University of Washington Medical Center, Seattle, Washington.
authors.forename: Shilpen
authors.initials: S
authors.lastname: Patel
mesh_terms: D006801:Humans; D009367:Neoplasm Staging / Q000401:mortality; D064887:Observational Studies as Topic; D011182:Postoperative Care / Q000401:mortality; D011379:Prognosis; D017594:Publication Bias; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D012189:Retrospective Studies; D016019:Survival Analysis; D013945:Thymoma / Q000401:mortality* / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D013953:Thymus Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery