Volume of Abnormal Tumor Tissue on FDG-PET -A Predictor of Progression-free Survival in Hodgkin's Lymphoma?

Reviewer: Christopher Dolinsky, MD
University of Pennsylvania School of Medicine
Ultima Vez Modificado: 18 de octubre del 2005

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Presenter: Martin Hutchings
Presenter's Affiliation: Copenhagen University Hosptial, Copenhagen, Denmark
Type of Session: Scientific

Background

  • Pre-treatment tumor volume is a well characterized independent risk factor for developing tumor recurrence in Hodgkin's Lymphoma.
  • PET scans offer quantitative data regarding the glucose utilization of both tumor and normal tissue.
  • PET scans have become important in the staging and follow-up for patients with Hodgkin's Lymphoma.
  • A large amount of tumor mass seen on PET imaging in Hodgkin's Lymphoma may be related to inflammation rather than actual malignant cells.

Materials and Methods

  • 65 patients with Hodgkin's Disease were enrolled on this prospective trial.
  • Each patient had a PET/CT before treatment.
  • The metabolic tumor volume was determined by measuring the areas of abnormal FDG uptake on CT scan.
  • The patient sample was typical for adult Hodgkin's patients, with a slight male predominance and a median age of 36 years old.
  • The predominant histology was nodular sclerosing HD (43%).
  • Patient's received 2, 4, 6, or 8 cycles of ABVD chemotherapy.
  • Median follow-up was 24 months.

Results

  • 400 ml was determined as the appropriate cut-off separating low-volume from high-volume disease based on the data collected, and this analysis was done in a retrospective fashion using receiver operating curves.
  • Progression was seen in 8/22 patients with high volume disease and 4/43 patients with low volume disease; this difference reach statistical significance.
  • IPS score was related to an increased likelihood of disease progression

Author's Conclusions

  • A large volume of metabolic tumor volume predicts progressive disease in newly diagnosed Hodgkin's disease.
  • Larger numbers of patients and events will be needed to test for the independence of other prognostic factors.

Clinical/Scientific Implications

 PET scans have become increasingly utilized in this disease, and there is a lack of good data to help drive research and clinical decisions based on PET findings. Of particular debate is how to proceed with treatment after a patient with early stage Hodgkin's Lymphoma has complete resolution of PET signal after chemotherapy. Although most institutions are performing the scans, there is a lack of consensus on how to use them. Because the cut-off of 400ml was determined retrospectively in this research, this definition of high volume disease needs to be prospectively validated. This research must be considered hypothesis generating, not hypothesis proving. If it can be shown that pre-treatment PET characteristics can accurately predict for treatment failures, then more aggressive therapeutic strategies can be tested in those patients.

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