Early Metabolic Response as a Predictor of Treatment Outcome in Patients With Metastatic Soft Tissue Sarcomas

Anticancer Res. 2019 Mar;39(3):1309-1316. doi: 10.21873/anticanres.13243.


Background/aim: Pazopanib is approved for advanced soft tissue sarcoma (STS) patients. The aim of the study was to examine the usefulness of (18F)-Fluorodeoxyglucose-positron emission tomography/ computed tomography (FDG-PET/CT) imaging for early evaluation of the response of STS patients to pazopanib, as well as the association between pazopanib pharmacokinetics and early metabolic response.

Patients and methods: Twenty STS patients underwent FDG-PET scans at baseline, two- and eight-weeks following treatment with pazopanib. The FDG-PET scans were evaluated by quantitative PERCIST analysis and visually by an independent nuclear medicine physician and related to RECIST1.1 outcome at eight weeks.

Results: After eight weeks of therapy, 14 out of 20 patients had discontinued pazopanib due to tumor progression identified radiologically ('non-responders' n=12) or toxicity (n=2). Quantitative FDG-PET scoring at two weeks, according to PERCIST guidelines, identified 25% (3 of 12) of the patients radiologically as non-responders versus 42% (5 of 12) identified by visual response analysis.

Conclusion: In this heterogeneous STS patients' cohort, early FDG-PET/CT identified a substantial part of pazopanib non-responders.

Keywords: Sarcoma; pazopanib; pharmacodynamics; pharmacokinetics; positron-emission tomography; soft tissue.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Aged
  • Angiogenesis Inhibitors / pharmacokinetics*
  • Angiogenesis Inhibitors / therapeutic use*
  • Feasibility Studies
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Male
  • Middle Aged
  • Positron Emission Tomography Computed Tomography
  • Pyrimidines / pharmacokinetics*
  • Pyrimidines / therapeutic use*
  • Sarcoma* / diagnostic imaging
  • Sarcoma* / drug therapy
  • Sarcoma* / metabolism
  • Sarcoma* / pathology
  • Sulfonamides / pharmacokinetics*
  • Sulfonamides / therapeutic use*
  • Treatment Outcome


  • Angiogenesis Inhibitors
  • Pyrimidines
  • Sulfonamides
  • Fluorodeoxyglucose F18
  • pazopanib