title: A clinicopathological study of resected adenocarcinoma 2 cm or less in diameter.
abstract: BACKGROUND
  The biological behavior of small adenocarcinoma is different in each patient and these are especially enormous differences when evaluating solid tumors and nonsolid tumors.
  
  
  METHODS
  A total of 159 adenocarcinomas 2 cm or less in diameter were studied. Several clinicopathological factors were retrospectively analyzed.
  
  
  RESULTS
  The diameter of the primary tumors was less than 1 cm in 47 patients, 1-1.5 cm in 49 patients, and 1.5-2 cm in 63 patients, respectively. Almost all patients (147) were pathologic N0 and there were 12 node-positive patients (7.5%). Lymph-node involvement was observed in 1 patient with a tumor diameter measuring less than 1 cm and in 11 patients with a tumor diameter measuring 1-2 cm. According to Noguchi' s classification, 33 patients belonged to class A or B, 71 patients belonged to class C, and 55 patients belonged to class D, E, or F. The ratio of ground-glass opacity (GGO) area in the main tumor in high resolution computed tomography was classified into two groups with a threshold of 50%. There were 44 patients with a GGO ratio of equal to or greater than 50%, none of which indicated lymph-node metastasis or tumor recurrence during follow-up (5-year survival = 100%). On the contrary among 115 patients with a GGO ratio less than 50%, lymph-node involvement was indicated in 12 patients (10.4%) and the 5-year survival rate was 83.9%.
  
  
  CONCLUSIONS
  The biological malignancy of small adenocarcinomas might be accurately evaluated by the proportion of GGO area as well as the Noguchi classification.
authors.affiliation: Department of Thoracic Surgery, Tokyo Medical University, Tokyo, Japan. ikeda@wd5.so-net.ne.jp
authors.forename: Norihiko
authors.initials: N
authors.lastname: Ikeda
authors.forename: Junichi
authors.initials: J
authors.lastname: Maeda
authors.forename: Koichi
authors.initials: K
authors.lastname: Yashima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tsuboi
authors.forename: Harubumi
authors.initials: H
authors.lastname: Kato
authors.forename: Soichi
authors.initials: S
authors.lastname: Akada
authors.forename: Shinya
authors.initials: S
authors.lastname: Okada
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000601:surgery*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed