title: Clinical Significance of Positron Emission Tomography in Subcentimeter Non-Small Cell Lung Cancer.
abstract: BACKGROUND
  This study evaluated the clinical significance of maximum standardized uptake value (SUVmax) on positron emission tomography (PET) in patients with subcentimeter non-small cell lung cancer (NSCLC).
  
  
  METHODS
  Between 2008 and 2014, 189 patients were investigated preoperatively by PET for c-N0 subcentimeter NSCLC, and SUVmax was reviewed. Pathologic invasiveness (PI) was defined as having at least one of the following factors: lymphatic invasion, vascular invasion, pleural invasion, or nodal metastasis. Survival rates were calculated by Kaplan-Meier estimation methods using the log-rank test.
  
  
  RESULTS
  Mean SUVmax was 1.7 ± 1.8 (range, 0.6 to 13.0), and the median was 1.0. PI was found in 28 (15%) patients with subcentimeter NSCLC. Multivariate analysis revealed that SUVmax was an independent significant clinical predictor of PI (p = 0.0251) and a prognostic factor of overall survival (OS) (p = 0.0485). A receiver operating characteristics curve elucidated the predictive cutoff value of PI as SUVmax = 2.0. The high-SUVmax group (SUVmax >2.0; n = 42) had significantly more radiologically pure-solid lesions (91% vs 14%; p < 0.0001) and postoperative nodal involvement (12% vs 0%; p < 0.0001) than the low-SUVmax group (SUVmax ≤2.0; n = 147). The 5-year lung cancer-specific OS (LCS-OS) elucidated significant difference between the high-SUVmax and low-SUVmax arms of the study (LCS-OS: 92.3% vs 96.9%, respectively; p = 0.0054), and cancer recurrence was found exclusively in pure-solid subcentimeter NSCLC on thin-section computed tomography. In the high-SUVmax arm of the study, lobectomy was associated with better 3-year recurrence-free survival compared with sublobar resection despite the subcentimeter disease (88.3% vs 50.0%; p = 0.0453).
  
  
  CONCLUSIONS
  SUVmax on PET reflected tumor invasiveness and had a great impact on the prognosis of subcentimeter NSCLC, especially when a tumor showed a pure-solid appearance on a thin-section computed tomography scan.
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan. Electronic address: ahattori@juntendo.ac.jp.
authors.forename: Aritoshi
authors.initials: A
authors.lastname: Hattori
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Takamochi
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Shiaki
authors.initials: S
authors.lastname: Oh
authors.affiliation: Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D049268:Positron-Emission Tomography; D011379:Prognosis; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18