title: Radiologic findings to predict low-grade malignant tumour among clinical T1bN0 lung adenocarcinomas: lessons from histological subtypes.
abstract: OBJECTIVE
  Some clinical T1bN0 (cT1bN0) lung adenocarcinomas (2-3 cm) are thought to have less-aggressive and less-malignant behaviour although most cT1aN0 tumours (≤2 cm) are indolent. The present study aimed to identify pre-operative radiographic findings that can predict cT1bN0 lung adenocarcinoma with low-malignant aggressiveness in consideration of histological subtypes.
  
  
  METHODS
  The clinicopathological features and prognoses of 224 consecutive patients (histological subtype set, n = 122; prognosis set, n = 224) with cT1bN0 lung adenocarcinoma were retrospectively examined. Adenocarcinoma in situ, minimally invasive adenocarcinoma, lepidic, node-negative papillary and node-negative acinar predominant invasive adenocarcinomas were defined as low-grade malignant, whereas solid, micropapillary, node-positive acinar and node-positive papillary predominant invasive adenocarcinoma were defined as high-grade malignant.
  
  
  RESULTS
  Receiver operating characteristics analysis revealed that the criteria of solid tumour size ≤1.8 cm on high-resolution computed tomography and the maximum standardized uptake value ≤3.2 on positron emission tomography/computed tomography could predict low-grade malignant tumour in the histological subtype set. Among 95 (42.4%) of 224 patients who met the criteria for the prognosis set, 94 (98.9%) had no lymph node metastasis and 93 (97.9%) had no recurrence (median follow-up, 43.6 months). The 3 year recurrence-free survival rates were 94.9 and 79.0% in patients whose pre-operative findings met and did not meet the criteria, respectively.
  
  
  CONCLUSIONS
  Pre-operative radiographic findings of solid tumour size and the maximum standardized uptake value could identify low-grade malignant tumour among cT1bN0 lung adenocarcinomas, which account for about half of all cT1bN0 tumours. Patients with pre-operative lung tumour findings that fulfill the criteria could be candidates for sublobar resection.
authors.affiliation: Department of Surgical Oncology, Hiroshima University, Hiroshima.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Mimae
authors.affiliation: Department of Surgical Oncology, Hiroshima University, Hiroshima.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Miyata
authors.affiliation: Department of Surgical Oncology, Hiroshima University, Hiroshima.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mimura
authors.affiliation: Department of Thoracic Surgery, Kanagawa Cancer Centre, Yokohama.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Thoracic Surgery, Kanagawa Cancer Centre, Yokohama.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Nakayama
authors.affiliation: Department of Thoracic Surgery, Cancer Institute Hospital, Tokyo.
authors.forename: Sakae
authors.initials: S
authors.lastname: Okumura
authors.affiliation: Department of Thoracic Surgery, Hyogo Cancer Centre, Akashi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoshimura
authors.affiliation: Department of Surgical Oncology, Hiroshima University, Hiroshima morihito1217@hiroshima-u.ac.jp.
authors.forename: Morihito
authors.initials: M
authors.lastname: Okada
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: SUVmax; lung adenocarcinoma; solid tumour size; sublobar resection; subtypes