title: Prediction for prognosis of resected pT1a-1bN0M0 adenocarcinoma based on tumor size and histological status: relationship of TNM and IASLC/ATS/ERS classifications.
abstract: OBJECTIVE
  This study aimed to estimate the relationship between 7th TNM classification and IASLC/ATS/ERS classification with regard to tumor size and pathological status and to determine the utility of these classifications for predicting prognosis in resected node-negative adenocarcinoma with tumor size ≤2.0 cm and >2.0-3.0 cm.
  
  
  METHODS
  We reviewed 321 pN0M0 lung adenocarcinoma cases resected at Hiroshima University Hospital from January 1991 to December 2010. Histological differences between T1a and T1b based on the IASLC/ATS/ERS classification were estimated and followed by evaluation of overall survival (OS) and recurrence-free interval (RFI) based on differences in tumor size and histological features.
  
  
  RESULTS
  We found 188 cases of pT1a-1bN0M0 (135 T1a, 53 T1b). Pathological T1a tumors included significantly more adenocarcinoma in situ (AIS) cases and minimally invasive adenocarcinoma (MIA) cases than T1b tumors (60.7% vs 18.8%, respectively; p<0.0001), while more invasive adenocarcinoma cases were included in pT1b. By considering the two classifications simultaneously, the 5-year OS rates of T1a AIS/MIA, T1b AIS/MIA, T1a invasive adenocarcinoma, and T1b invasive adenocarcinoma were 97.5%, 87.5%, 95.8%, and 86.8%, respectively. The 5-year RFIs of T1a AIS/MIA, T1b AIS/MIA, T1a invasive adenocarcinoma, and T1b invasive adenocarcinoma were 100%, 100%, 91.3%, and 72.5%, respectively. T1a AIS/MIA and T1b AIS/MIA could be separated as good prognostic cases with a 100% RFI. Multivariate analysis indicated that only T1b invasive adenocarcinoma was an independent factor for predicting recurrence (p=0.001).
  
  
  CONCLUSIONS
  Compared to a single classification, combining TNM and IASLC/ATS/ERS classifications could provide more detail information concerning disease recurrence. AIS and MIA should be handled equally, regardless of tumor size, because their non-/less invasive status is more useful for predicting prognosis than their tumor size classification. In contrast, the T descriptors based on TNM classification are important for predicting prognosis in invasive adenocarcinoma.
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Masaoki
authors: M
authors: Ito
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. Electronic address: ymiyata@hiroshima-u.ac.jp.
authors: Yoshihiro
authors: Y
authors: Miyata
authors: Department of Pathology, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Kei
authors: K
authors: Kushitani
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Tomoharu
authors: T
authors: Yoshiya
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Takahiro
authors: T
authors: Mimae
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Yuta
authors: Y
authors: Ibuki
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Keizo
authors: K
authors: Misumi
authors: Department of Pathology, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Yukio
authors: Y
authors: Takeshima
authors: Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors: Morihito
authors: M
authors: Okada
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D000077192:Adenocarcinoma of Lung; D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D016017:Odds Ratio; D011013:Pneumonectomy; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Adenocarcinoma; In situ; Invasive; Lung cancer; Prognosis; Recurrence; Tumor staging