title: Thoracoscopic thymectomy is a feasible and less invasive alternative for the surgical treatment of large thymomas.
abstract: Thoracoscopic surgery is widely used for the surgical treatment of thymoma. However, large-sized thymomas are typically treated using open surgery. This study evaluated the feasibility of performing thoracoscopic thymectomy (TT) for thymoma ≥50 mm.
  
  
  
  A retrospective review was conducted on 135 patients who underwent TT or open thymectomy (OT) for Masaoka stage I-IVa thymoma between 1996 and 2014.
  
  
  
  Patients were first divided into two groups based on thymoma size: thymoma ≥50 mm and thymoma <50 mm groups. There was no significant difference in the 5-year disease-free survival (DFS) between the groups ( P  = 0.5352). Patients in the thymoma ≥50 mm group were further subdivided into TT and OT groups. The length of postoperative hospital stay was significantly shorter in the TT group than in the OT group (5 vs 14 days, P  < 0.0001), with significantly fewer postoperative complications (6 patients vs 14 patients, P  = 0.0008). There was no significant difference in the 5-year DFS between patients with thymoma ≥50 mm in the TT and OT groups ( P  = 0.3501). Finally, patients undergoing TT were further subdivided into thymoma ≥50 mm and thymoma <50 mm groups and, no significant difference in the 5-year DFS was found between these groups ( P  = 0.6661). Masaoka stages III-IV, but not thymoma size, were an independent prognostic factor for DFS.
  
  
  
  These results demonstrate the decreased invasiveness and feasibility of TT for large-sized thymomas.
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Odaka
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: You
authors.initials: Y
authors.lastname: Tsukamoto
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Shibasaki
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Katou
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Mori
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Asano
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamashita
authors.affiliation: Department of Surgery, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Morikawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D020775:Thoracic Surgery, Video-Assisted / Q000379:methods*; D013934:Thymectomy / Q000379:methods*; D013945:Thymoma / Q000175:diagnosis / Q000601:surgery*; D013953:Thymus Neoplasms / Q000175:diagnosis / Q000601:surgery*; D047368:Tumor Burden; D055815:Young Adult
keywords: Large ; Thoracoscopic thymectomy; Thymoma