title: Clinical evaluation of a new tumour-node-metastasis staging system for thymic malignancies proposed by the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee and the International Thymic Malignancy Interest Group.
abstract: OBJECTIVE
  The tumour-node-metastasis classification has been widely used as a guide for estimating prognosis, and is the basis for treatment decisions in patients with malignant tumours. The International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee and the International Thymic Malignancy Interest Group have proposed a new staging system for thymic malignancies. However, its validity has not been fully established. In this study, we assessed the system's utilities and drawbacks.
  
  
  METHODS
  We reviewed 154 consecutive patients with thymic epithelial tumours who underwent complete resection at our institution, and compared their characteristics and outcomes when classified according to the proposed system with those when classified under the Masaoka-Koga system.
  
  
  RESULTS
  The proportion of patients with Stage I disease increased remarkably to 77.3% when using the proposed system because of the reclassification of Masaoka-Koga stages II and III diseases. Among 69 patients with Type A, AB or B1 thymoma, 68 tumours (98%) were reclassified as Stage I disease. Moreover, the proportion of Stage III and IV tumours increased in concordance with Types B2, B3 thymomas and thymic carcinoma. Under the proposed new system, the recurrence-free survival rates showed significant deterioration with increasing stage, while the overall survival curves did not.
  
  
  CONCLUSIONS
  The newly proposed classification for thymic malignancies does not serve as a prognostic prediction model for overall survival but served as a significant imbalance of stage distribution in our cohort. However, it appears to be beneficial, especially in clinical settings and recurrence-free survival analysis.
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; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009375:Neoplasms, Glandular and Epithelial / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D018358:Neuroendocrine Tumors / Q000401:mortality / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D013945:Thymoma / Q000401:mortality / Q000473:pathology / Q000601:surgery; D013953:Thymus Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery
keywords: TNM classification; Thymic carcinoma; Thymoma; Thymus