title: Prognostic impact of tumour size in completely resected thymic epithelial tumours.
abstract: OBJECTIVE
  The T descriptor of thymic epithelial tumours proposed by the International Association for the Study of Lung Cancer and the International Thymic Malignancy Interest Group as well as the Masaoka-Koga system is defined by the anatomical extent of primary tumours, regardless of their size. However, the prognostic significance of tumour size in thymic epithelial tumours has not been fully elucidated.
  
  
  METHODS
  We evaluated the prognostic significance of tumour size in 154 consecutive patients with thymic epithelial tumours including 124 thymomas, 21 thymic carcinomas and 9 neuroendocrine tumours, who underwent complete resection between 2001 and 2014.
  
  
  RESULTS
  Among all tumours, the median tumour size was 4.9 cm. The median thymoma, thymic carcinoma and neuroendocrine tumour sizes were 4.8, 5.7 and 5.8, respectively, although the differences were not significant. In survival analysis, the 5- and 10-year overall survival (OS) and recurrence-free survival (RFS) rates for all patients were 91 and 81%, and 80 and 69%, respectively. Under the stratification of tumour size, no trend was observed for OS, whereas RFS showed stepwise deterioration as tumour size increased. For 119 patients with Stage I disease, RFS showed deterioration as tumour size increased. Multivariate analysis revealed that tumour size >4.0 cm was an independent prognostic factor for worsening RFS (P = 0.03).
  
  
  CONCLUSIONS
  Patients with tumours >4.0 cm showed significantly worse outcomes in RFS compared with those with smaller tumours. This relationship was also noted in patients with Stage I disease.
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan tfukui@med.nagoya-u.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fukui
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Fukumoto
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Okasaka
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kawaguchi
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Hakiri
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ozeki
authors.affiliation: Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hirakawa
authors.affiliation: Department of Pathology, Kasugai Municipal Hospital, Kasugai, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tateyama
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Yokoi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000175:diagnosis / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000401:mortality / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D016019:Survival Analysis; D013945:Thymoma / Q000175:diagnosis / Q000401:mortality / Q000473:pathology / Q000601:surgery; D013950:Thymus Gland / Q000473:pathology* / Q000601:surgery; D013953:Thymus Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D055815:Young Adult
keywords: TNM classification; Thymic carcinoma; Thymoma; Thymus