title: Pattern of metastasis outside tumor-bearing segments in primary lung cancer: rationale for segmentectomy.
abstract: BACKGROUND
  Patterns of intrapulmonary metastasis, particularly metastasis outside tumor-bearing segments, were investigated in lung cancer patients to address the rationale for segmentectomy.
  
  
  METHODS
  In a consecutive series of patients who underwent resection of two or more pulmonary segments for primary lung cancer, intrapulmonary spread patterns, such as segmental/intersegmental node metastasis and pulmonary parenchymal metastasis, were pathologically examined.
  
  
  RESULTS
  Eligible 244 lesions included 167 adenocarcinomas, 66 squamous cell carcinomas, and 11 large cell carcinomas. Pathologic stages included 0 to IA (n=111), IB (n=56), IIA (n=31), IIB (n=20), IIIA (n=23), and IIIB to IV (n=3); and N1 (n=26) and N2 (n=22). Intrapulmonary spread was observed in 24 cases (9.8%). Of these, metastasis outside tumor-bearing segments was only observed in 4 cases (1.6%), and such cancer spread was more frequently seen in cases with extrapulmonary (hilar to mediastinal) nodal metastasis (7.9%) than in cases without extrapulmonary metastasis (0.5%; p=0.01). Metastasis outside tumor-bearing segments was not observed in 64 tumors with pure or mixed ground glass opacity features on computed tomography. Although tumor location (peripheral or central/intermediate) was not related to the incidence of metastasis outside tumor-bearing segments, intrapulmonary spread was observed in only 1 of 52 peripheral small (≤20 mm) tumors.
  
  
  CONCLUSIONS
  Metastasis outside tumor-bearing segments is rarely observed in cases with tumors (1) without extrapulmonary nodal metastasis and (2) with ground glass opacity or peripheral small (≤20 mm) features.
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan. Electronic address: y_sakairi1@chiba-u.jp.
authors: Yuichi
authors: Y
authors: Sakairi
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors: Ichiro
authors: I
authors: Yoshino
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors: Shigetoshi
authors: S
authors: Yoshida
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors: Hidemi
authors: H
authors: Suzuki
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors: Tetsuzo
authors: T
authors: Tagawa
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors: Takekazu
authors: T
authors: Iwata
authors: Department of General Thoracic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors: Teruaki
authors: T
authors: Mizobuchi
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000556:secondary / Q000601:surgery; D000368:Aged; D018287:Carcinoma, Large Cell / Q000401:mortality / Q000556:secondary / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000556:secondary / Q000601:surgery; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000379:methods* / Q000401:mortality; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D016896:Treatment Outcome