[(18)F]FDG PET monitoring of tumour response to chemotherapy: does [(18)F]FDG uptake correlate with the viable tumour cell fraction?

Eur J Nucl Med Mol Imaging. 2003 May;30(5):682-8. doi: 10.1007/s00259-003-1120-6. Epub 2003 Feb 25.


Because metabolic changes induced by chemotherapy precede the morphological changes, fluorine-18 fluorodeoxyglucose positron emission tomography ([(18)F]FDG PET) is thought to predict response to therapy earlier and more accurately than other modalities. To be a reliable predictor of response, changes in tumour [(18)F]FDG uptake should reflect changes in viable cell fraction, but little is known about the contribution of apoptotic and necrotic cancer cells and inflammatory tissue to the [(18)F]FDG signal. In a tumour mouse model we investigated the relation between chemotherapy-induced changes in various tumoral components and tumour uptake and size. SCID mice were subcutaneously inoculated in the right thigh with 5 x 10(6) Daudi cells. When the tumour measured 15-20 mm, Endoxan was given intravenously. At different time points [1-15 days (d1-d15) after the injection of Endoxan], ex vivo autoradiography and histopathology were performed in two mice and [(18)F]FDG uptake in the tumour and tumour size were correlated with the different cell fractions measured with flow cytometry in five mice. At d1/d3, similar reductions in [(18)F]FDG uptake and viable tumoral cell fraction were observed and these reductions preceded changes in tumour size. By d8/d10, [(18)F]FDG uptake had stabilised despite a further reduction in viable tumoral cell fraction. At these time points a major inflammatory response was observed. At d15, an increase in viable tumour cells was again observed and this was accurately predicted by an increase in [(18)F]FDG uptake, while the tumour volume remained unchanged. In contrast with variations in tumour volume, [(18)F]FDG is a good marker for chemotherapy response monitoring. However, optimal timing seems crucial since a transient increase in stromal reaction may result in overestimation of the fraction of viable cells.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents, Alkylating / therapeutic use
  • Apoptosis / drug effects
  • Burkitt Lymphoma / diagnostic imaging*
  • Burkitt Lymphoma / drug therapy*
  • Burkitt Lymphoma / metabolism
  • Burkitt Lymphoma / pathology
  • Cell Division / drug effects
  • Cyclophosphamide / therapeutic use*
  • Drug Therapy / methods
  • Female
  • Fluorodeoxyglucose F18 / pharmacokinetics*
  • Humans
  • Male
  • Mice
  • Mice, SCID
  • Neoplasm Transplantation
  • Radionuclide Imaging
  • Radiopharmaceuticals* / pharmacokinetics
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Statistics as Topic
  • Treatment Outcome


  • Antineoplastic Agents, Alkylating
  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18
  • Cyclophosphamide