title: Results of T4 surgical cases in the Japanese Lung Cancer Registry Study: should mediastinal fat tissue invasion really be included in the T4 category?
abstract: BACKGROUND
  T4 lung cancer is a heterogeneous group of locally advanced disease. We hypothesized that patients in whom T4 lung cancer invaded only mediastinal fat tissue would show better prognosis after surgery than patients in whom T4 disease invaded other organs. The present study aimed to investigate how different invasive features of T4 disease impacted prognosis, and what types of patients with T4 disease could benefit most from surgical treatment.
  
  
  METHODS
  A nationwide registry study on lung cancer surgical cases during 2004 was conducted by the Japanese Joint Committee of Lung Cancer Registry, including registries of 11,663 cases within Japan. The present study analyzed 215 of these cases involving T4 structures or with ipsilateral nonprimary lobe pulmonary metastasis (PM).
  
  
  RESULTS
  Reasons for T4 classification included invasion of only mediastinal tissue in 32 cases (15%), invasion of other structures in 96 cases (45%), and ipsilateral different lobe PM in 87 cases (40%); among these three groups, there were no significant differences in survival, nodal status, and patterns of first recurrence. Multivariate analysis showed an age of 70 years or above (p = 0.022) and nodal status (p = 0.004) to be significant prognostic factors. T4N0 patients less than 70 years of age showed significantly better prognosis than those who were T4N1-2 and 70 years of age or older (p = 0.0001; 5-year survival rate 50.3 versus 19.9%).
  
  
  CONCLUSIONS
  There was no significant difference in survival between T4 patients with only mediastinal fat invasion and those with other T4 organ invasion and ipsilateral different lobe PM, demonstrating appropriateness of the T4 category definition in the current tumor, node, metastasis staging system. Age and nodal status were significant independent prognostic factors in T4 patients, and the best surgical candidates were shown to be T4N0 patients who were less than 70 years of age and had a 5-year survival rate of more than 50%.
authors.affiliation: Division of Thoracic Surgery, National Cancer Center Hospital, Tokyo, Japan. syuwatan@ncc.go.jp
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Hisao
authors.initials: H
authors.lastname: Asamura
authors.forename: Etsuo
authors.initials: E
authors.lastname: Miyaoka
authors.forename: Meinoshin
authors.initials: M
authors.lastname: Okumura
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yoshino
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Fujii
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Kenji
authors.initials: K
authors.lastname: Eguchi
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Sawabata
authors.forename: Kohei
authors.initials: K
authors.lastname: Yokoi
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000401:mortality*; D011379:Prognosis; D015996:Survival Rate