18F-fluorodeoxyglucose Positron Emission Tomography in the Management of Patients With Thymic Epithelial Tumors

Clin Cancer Res. 2013 Mar 15;19(6):1487-93. doi: 10.1158/1078-0432.CCR-12-2929. Epub 2013 Feb 4.

Abstract

Purpose: There are limited data regarding the role of (18)F-fluorodeoxyglucose positron emission tomography ([(18)F]-FDG PET) imaging in management of patients with thymic epithelial tumors (TET). The primary objective of this study was to assess the usefulness of early [(18)F]-FDG PET to monitor treatment efficacy and its correlation with Response Evaluation Criteria in Solid Tumors (RECIST) in patients with TETs.

Experimental design: [(18)F]-FDG PET/computed tomographic (CT) scans were conducted at baseline and after 6 weeks of treatment in patients enrolled in two phase II and one phase I/II clinical trials. On the basis of data from other solid tumors, metabolic response was defined as a reduction of [(18)F]-FDG uptake by more than 30% as assessed by average standardized uptake values (SUV) of up to five most metabolically active lesions.

Results: Fifty-six patients with unresectable Masaoka stage III or IV TETs were included. There was a close correlation between early metabolic response and subsequent best response using RECIST (P < 0.0001-0.0003): sensitivity and specificity for prediction of best response were 95% and 100%, respectively. Metabolic responders had significantly longer progression-free survival (median, 11.5 vs. 4.6 months; P = 0.044) and a trend toward longer overall survival (median, 31.8 vs. 18.4 months; P = 0.14) than nonresponders. [(18)F]-FDG uptake was significantly higher in thymic carcinoma than in thymoma (P = 0.0004-0.0010).

Conclusion: In patients with advanced TETs, early metabolic response closely correlates with outcome of therapy. [(18)F]-FDG PET may be used to monitor treatment efficacy and assess histologic differences in patients with advanced TETs.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Clinical Trials, Phase I as Topic
  • Clinical Trials, Phase II as Topic
  • Diagnostic Imaging / methods*
  • Disease-Free Survival
  • Female
  • Fluorodeoxyglucose F18 / administration & dosage*
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Neoplasms, Glandular and Epithelial / diagnostic imaging*
  • Neoplasms, Glandular and Epithelial / drug therapy
  • Neoplasms, Glandular and Epithelial / pathology
  • Positron-Emission Tomography / methods*
  • Radiography
  • Thymus Neoplasms / diagnostic imaging*
  • Thymus Neoplasms / drug therapy
  • Thymus Neoplasms / pathology

Substances

  • Fluorodeoxyglucose F18

Supplementary concepts

  • Thymic epithelial tumor