title: Postoperative radiotherapy and tumor recurrence after complete resection of stage II/III thymic tumor: a meta-analysis of cohort studies.
abstract: BACKGROUND
  Whether postoperative radiotherapy (PORT) is effective for reducing the recurrence risk in patients who received complete resection of the stage II or III thymic tumors has not been determined. A meta-analysis was performed by combining the results of all available controlled trials.
  
  
  METHODS
  PubMed, Cochrane's Library, and the Embase databases were searched for studies which compared the recurrence data for patients with complete resection of the stage II or III thymic tumors assigned to an observing group, or a PORT group. A random effect model was applied to combine the results.
  
  
  RESULTS
  Nineteen studies, all designed as retrospective cohort studies were included. These studies included 663 patients of PORT group and 617 patients of observing group. The recurrence rate for the patients in PORT group and observing group were 12.4% and 11.5%, respectively. Results of our study indicated that PORT has no significant influence on recurrent risk in patients with stage II or III thymic tumor after complete resection (odds ratio 1.02, 95% confidence interval 0.55-1.90, P=0.96). When stratified by stages, our meta-analyses did not indicate any significant effects of PORT on recurrent outcomes in either the stage II or the stage III patients. Moreover, subsequent analysis limited to studies only including patients with thymoma or thymic carcinoma also did not support the benefits of PORT on recurrent outcomes.
  
  
  CONCLUSIONS
  Although derived from retrospective cohort studies, current evidence did not support any benefit of PORT on recurrent risk in patients with complete resection of the stage II or III thymic tumors.
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Jietao
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Letian
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Xiong
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Yuan
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Shuling
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Cheng-Bo
authors.initials: CB
authors.lastname: Han
keywords: meta-analysis; postoperative radiotherapy; recurrence; thymic tumor