title: Role of lymphatic invasion in the prognosis of patients with clinical node-negative and pathologic node-positive lung adenocarcinoma.
abstract: OBJECTIVE
  Some patients with clinical T1 N0 M0 lung adenocarcinoma have pathologic lymph node metastasis. However, neither the precise prognosis nor the factors predictive of the prognosis of such patients have yet been identified.
  
  
  METHODS
  Our study included 609 patients with clinical T1 N0 M0 lung adenocarcinoma; 568 (93.3%) pathologic node negative [pN(-)] and 41 (6.7%) pathologic node positive [pN(+)] patients, diagnosed after complete surgical resection. The association between prognosis and pathologic findings was analyzed retrospectively.
  
  
  RESULTS
  pN(+) patients had a significantly lower lepidic growth component ratio (10% vs 50%), a higher lymphatic invasion (LI) rate (68% vs 11%), vessel invasion rate (59% vs 14%), and visceral pleural invasion rate (29% vs 9%), compared with pN(-) patients (all Ps < .001). Surprisingly, 13 of 41 (32%) pN(+) patients showed no LI. In pN(-) patients, a multivariate analysis of recurrence-free survival revealed that lower lepidic growth component ratio, and lymphatic, vessel, and pleural invasion were significantly correlated with a poor prognosis (P = .008, .045, .031, and .024). However, in pN(+) patients, the multivariate analysis of recurrence-free survival showed that only LI was a significant independent prognostic factor (P = .037). The 5-year recurrence-free survival rates were as follows: 91.2% for pN(-)/LI(-) patients, 68.2% for pN(-)/LI(+) patients, 63.5% for pN(+)/LI(-) patients, and 41.9% for pN(+)/LI(+) patients. LI status stratified the prognosis not only in patients with no nodal metastasis but also in those with metastasis.
  
  
  CONCLUSIONS
  LI, which is not always present in node-positive adenocarcinoma, is an important prognostic variable in patients with node involvement.
authors: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors: Takahiro
authors: T
authors: Mimae
authors: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors: Yasuhiro
authors: Y
authors: Tsutani
authors: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors: Yoshihiro
authors: Y
authors: Miyata
authors: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors: Tomoharu
authors: T
authors: Yoshiya
authors: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
authors: Yuta
authors: Y
authors: Ibuki
authors: Department of Pathology, Hiroshima University, Hiroshima, Japan.
authors: Kei
authors: K
authors: Kushitani
authors: Department of Pathology, Hiroshima University, Hiroshima, Japan.
authors: Yukio
authors: Y
authors: Takeshima
authors: Department of Thoracic Surgery, Kanagawa Cancer Center, Yokohama, Japan.
authors: Haruhiko
authors: H
authors: Nakayama
authors: Department of Thoracic Surgery, Cancer Institute Hospital, Tokyo, Japan.
authors: Sakae
authors: S
authors: Okumura
authors: Department of Thoracic Surgery, Hyogo Cancer Center, Akashi, Japan.
authors: Masahiro
authors: M
authors: Yoshimura
authors: Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan. Electronic address: morihito1217@hiroshima-u.ac.jp.
authors: Morihito
authors: M
authors: Okada
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D000077192:Adenocarcinoma of Lung; D000368:Aged; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011013:Pneumonectomy; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome