title: Prognostic evaluations of small size lung cancers by 18F-FDG PET/CT and thin-section CT.
abstract: OBJECTIVE
  Primary lung cancers have varying prognoses, even for tumors ≤3cm in diameter. Thus, a thorough evaluation is necessary for therapeutic planning. Two imaging biomarkers have been shown to be useful for predicting primary lung cancer prognosis: maximum standardized uptake values (SUVmax) on fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and the consolidation/tumor (C/T) ratio defined as the maximum diameter of consolidation within a tumor to the maximum tumor diameter on thin-section computed tomography (TSCT). We compared these biomarkers for predicting post-surgical recurrence in patients with small lung cancers.
  
  
  METHODS
  Clinical records, post-operative pathologic findings, and pre-operative PET/CT and TSCT images were reviewed. Solitary primary lung cancers of ≤3cm in diameter after surgical resection were selected for analysis. SUVmax and C/T ratios were recorded. Kaplan-Meier survival curves and Cox hazards ratios were used to identify independent predictors of lung cancer recurrence from among age, gender, surgical procedure, lesion size, C/T ratio, and SUVmax.
  
  
  RESULTS
  A total of 169 patients (114 males and 55 females; age range: 34-87 years) with solitary lung cancers were evaluated. The median post-operative follow-up period was 42 months. Twenty-eight patients had cancer recurrence with significantly higher SUVmax (p<0.001) and C/T ratios (p<0.001) than patients without recurrence. Disease-free survival was significantly reduced for SUVmax of ≥2.5 vs. SUVmax of <2.5 (p<0.001) or for a C/T ratio of ≥50% vs. a C/T ratio of <50% (p=0.030). For 19 patients with C/T ratios of <50%, none had a post-operative recurrence. A Cox hazards ratio model showed that only SUVmax was an independent predictor of recurrence (hazards ratio=1.324; p<0.001).
  
  
  CONCLUSIONS
  SUVmax on FDG-PET/CT was a significant imaging biomarker relevant to the prognosis of patients with lung cancers, and was superior to the C/T ratio on TSCT for predicting postoperative recurrence, particularly for solid type lung cancer.
authors.affiliation: Nagoya University Graduate School of Medicine, Department of Radiology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Kishimoto
authors.affiliation: Nagoya University Graduate School of Medicine, Department of Radiology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan. Electronic address: iwano45@med.nagoya-u.ac.jp.
authors.forename: Shingo
authors.initials: S
authors.lastname: Iwano
authors.affiliation: Nagoya University Graduate School of Medicine, Department of Radiology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Ito
authors.affiliation: Nagoya University Graduate School of Medicine, Department of Radiological and Medical Laboratory Sciences, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kato
authors.affiliation: Nagoya University Graduate School of Medicine, Department of Radiology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Rintaro
authors.initials: R
authors.lastname: Ito
authors.affiliation: Nagoya University Graduate School of Medicine, Department of Radiology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D047368:Tumor Burden
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Computed tomography; Consolidation/tumor ratio; Imaging biomarker; Lung cancer; Non-small cell carcinoma; Positron emission tomography; Prognosis; SUVmax