title: Adjuvant radiotherapy for completely resected stage 2 thymoma.
abstract: BACKGROUND
  The clinical benefit of postoperative mediastinal radiation for completely resected Masaoka stage 2 thymoma remains controversial. Due to its indolent nature and infrequent recurrences, no study has definitively determined the optimal approach.
  
  
  METHODS
  We retrospectively reviewed 175 consecutive patients who underwent thymic resection from January 1990 to July 2008 at the University of Pennsylvania. The primary endpoint was local recurrence, defined as recurrence within the surgical bed, treated by resection alone versus resection plus radiation. Patients with high recurrence risk were referred for adjuvant radiotherapy.
  
  
  RESULTS
  Seventy-four Masaoka stage 2 patients were resected; 62 underwent complete resections with adequate postsurgical follow-up. Thirty-seven patients received adjuvant radiotherapy and 25 patients were observed. The median radiation dose was 5040 cGy. The median follow-up for all patients was 52 months. The local recurrence rate was 3.2%. The proportion of recurrences in patients observed after surgery was 8% versus 0% in those who received adjuvant radiotherapy (P = .15). Size was not an independent predictor of recurrence (P = .81). The tumor-related death rate was 0%, and overall death rate was 3.2%. One death occurred in each group, observation, and radiation. There were no grade 3 or 4 complications with radiation.
  
  
  CONCLUSIONS
  Recurrence rates were low following resection of stage 2 thymoma either with or without adjuvant radiotherapy. Adjuvant radiotherapy, although well-tolerated, did not significantly decrease the local relapse rate. Differences may be observed in future studies of patients who are at higher risk for local recurrence, based on completeness of resection, World Health Organization histology, and tumor size.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Abigail T
authors.initials: AT
authors.lastname: Berman
authors.forename: Leslie
authors.initials: L
authors.lastname: Litzky
authors.forename: Virginia
authors.initials: V
authors.lastname: Livolsi
authors.forename: Sunil
authors.initials: S
authors.lastname: Singhal
authors.forename: John C
authors.initials: JC
authors.lastname: Kucharczuk
authors.forename: Joel D
authors.initials: JD
authors.lastname: Cooper
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Friedberg
authors.forename: Tracey L
authors.initials: TL
authors.lastname: Evans
authors.forename: James P
authors.initials: JP
authors.lastname: Stevenson
authors.forename: James M
authors.initials: JM
authors.lastname: Metz
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Hahn
authors.forename: Ramesh
authors.initials: R
authors.lastname: Rengan
mesh_terms: D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018714:Radiotherapy, Adjuvant; D013945:Thymoma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D013953:Thymus Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D016896:Treatment Outcome