title: Prognostic value of preoperative metabolic tumor volumes on PET-CT in predicting disease-free survival of patients with stage I non-small cell lung cancer.
abstract: BACKGROUND
  This study aimed to determine the relationship between the pre-operative metabolic tumor volume (MTV) and the disease-free survival (DFS) of patients with stage I non-small cell lung cancer (NSCLC) using F-18 2-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography-computed tomography (PET-CT) scanning.
  
  
  METHODS
  Data from sixty patients with stage I NSCLC who had undergone preoperative F-18 FDG PET-CT scanning were retrospectively analyzed. The early and late maximum standardized uptake values (eSUVm and lSUVm, respectively) were measured from attenuation-corrected F-18 FDG PET-CT images. Three MTV segmentation methods were applied as an isocontour at an early SUV of 2.5 (MTV2.5) or using fixed thresholds of either 40% (MTV40%) or 50% (MTV50%) of the maximum intratumoral F-18 FDG activity. DFS was compared by employing the Kaplan-Meier method, using the median values as cutoffs for each parameter. The log-rank test and Cox regression were performed to explore the effect of the different MTV variables on DFS. Time-dependent receiver operating characteristic (ROC) curves were created to evaluate the predictive performance.
  
  
  RESULTS
  During a median follow-up duration of 24 months, two patients died of disease progression, and 11 experienced recurrent tumors (eight intrathoracic tumors, two distant metastasis, and one both types of recurrences). The univariate analyses showed that pathological stage 1B, histological type of squamous cell carcinoma, male sex, maximum tumor size over 2 cm, eSUVm, lSUVm, and MTV2.5 were associated with reduced DFS. Patients who had tumors with large eSUVm or large lSUVm had a significantly lower 2-year DFS, compared with patients who had smaller tumors (65% vs. 96%, p=0.002; 63% vs. 96%, p=0.000). Patients with an MTV2.5 greater than 9.8 ml had a lower 2-year DFS than those with an MTV of 9.8 ml or greater (59 vs. 85%, p=0.02). However, multivariate analysis showed that lSUVm over 3.4 was the only parameter that exhibited an impact on DFS (p=0.05, hazard ratio=10.7), and the observed influence was marginal.
  
  
  CONCLUSIONS
  For patients with stage I NSCLC treated with surgery, preoperative MTV parameters have a limited prognostic value for predicting DFS.
authors.affiliation: Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Yin
authors.initials: Y
authors.lastname: Lin
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Lin
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
authors.forename: Kuo-Yang
authors.initials: KY
authors.lastname: Yen
authors.forename: Shang-Wen
authors.initials: SW
authors.lastname: Chen
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Yeh
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; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011300:Preoperative Care; D011379:Prognosis; D016016:Proportional Hazards Models; D012372:ROC Curve; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed