title: Risk-stratifying capacity of PET/CT metabolic tumor volume in stage IIIA non-small cell lung cancer.
abstract: OBJECTIVE
  Stage IIIA non-small cell lung cancer (NSCLC) is heterogeneous in tumor burden, and its treatment is variable. Whole-body metabolic tumor volume (MTVWB) has been shown to be an independent prognostic index for overall survival (OS). However, the potential of MTVWBto risk-stratify stage IIIA NSCLC has previously been unknown. If we can identify subgroups within the stage exhibiting significant OS differences using MTVWB, MTVWBmay lead to adjustments in patients' risk profile evaluations and may, therefore, influence clinical decision making regarding treatment. We estimated the risk-stratifying capacity of MTVWBin stage IIIA by comparing OS of stratified stage IIIA with stage IIB and IIIB NSCLC.
  
  
  METHODS
  We performed a retrospective review of 330 patients with clinical stage IIB, IIIA, and IIIB NSCLC diagnosed between 2004 and 2014. The patients' clinical TNM stage, initial MTVWB, and long-term survival data were collected. Patients with TNM stage IIIA disease were stratified by MTVWB. The optimal MTVWBcutoff value for stage IIIA patients was calculated using sequential log-rank tests. Univariate and multivariate cox regression analyses and Kaplan-Meier OS analysis with log-rank tests were performed.
  
  
  RESULTS
  The optimal MTVWBcut-point was 29.2 mL for the risk-stratification of stage IIIA. We identified statistically significant differences in OS between stage IIB and IIIA patients (p < 0.01), between IIIA and IIIB patients (p < 0.01), and between the stage IIIA patients with low MTVWB(below 29.2 mL) and the stage IIIA patients with high MTVWB(above 29.2 mL) (p < 0.01). There was no OS difference between the low MTVWBstage IIIA and the cohort of stage IIB patients (p = 0.485), or between the high MTVWBstage IIIA patients and the cohort of stage IIIB patients (p = 0.459). Similar risk-stratification capacity of MTVWBwas observed in a large range of cutoff values from 15 to 55 mL in stage IIIA patients.
  
  
  CONCLUSIONS
  Using MTVWBcutoff points ranging from 15 to 55 mL with an optimal value of 29.2 mL, stage IIIA NSCLC may be effectively stratified into subgroups with no significant survival difference from stages IIB or IIIB NSCLC. This may result in more accurate survival estimation and more appropriate risk adapted treatment selection in stage IIIA NSCLC.
authors.affiliation: Department of Radiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL, 60637, USA.
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Finkle
authors.affiliation: Department of Radiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL, 60637, USA.
authors.forename: Stephanie Y
authors.initials: SY
authors.lastname: Jo
authors.affiliation: Department of Surgery, University of Chicago, Chicago, IL, USA.
authors.forename: Mark K
authors.initials: MK
authors.lastname: Ferguson
authors.affiliation: Department of Nuclear Medicine, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Liu
authors.affiliation: Department of Nuclear Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Chenpeng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Radiology, BenQ Medical Center, Nanjing Medical University, Nanjing, Jiangsu Province, China.
authors.forename: Xuee
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Radiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL, 60637, USA.
authors.forename: Cindy
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Department of Radiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL, 60637, USA. ypu@radiology.bsd.uchicago.edu.
authors.forename: Yonglin
authors.initials: Y
authors.lastname: Pu
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography; D012189:Retrospective Studies; D018570:Risk Assessment; D047368:Tumor Burden
keywords: 2-deoxy-2-[18F]fluoro-D-glucose; FDG; Metabolic tumor burden; Metabolic tumor volume; NSCLC; Non-small cell lung cancer; Survival analysis; TNM stage