Abstract for presentation at 38th Annual Scientific Meeting of the Australian and New Zealand Society of Nuclear Medicine 2008

Dosimetric Analysis of Tumour Dose Following 131I-huA33 Radioimmunotherapy Studies in Patients with Metastatic Colorectal Carcinoma

  • Ms Bridget Chappell, Department of Nuclear Medicine, and Centre for P.E.T., Austin Health, Melbourne, Australia
  • Mr Tim Saunder, Department of Nuclear Medicine, and Centre for P.E.T., Austin Health, Melbourne, Australia
  • Dr Rebecca Herbertson, Ludwig Institute for Cancer Research; and Department of Medicine, University of Melbourne, Austin Hospital, Melbourne, Australia
  • Dr Niall Tebbutt, Ludwig Institute for Cancer Research; and Department of Medicine, University of Melbourne, Austin Hospital, Australia
  • Dr Fook Lee, Ludwig Institute for Cancer Research; and Department of Medicine, University of Melbourne, Austin Hospital, Melbourne, Australia
  • Dr Graeme O'Keefe, Department of Nuclear Medicine, and Centre for P.E.T., Austin Health. Melbourne, Australia
  • Dr Sze Ting Lee, Ludwig Institute for Cancer Research; and Deptartment of Medicine, University of Melbourne, Austin Hospital, Melbourne, Australia
  • A/Prof Andrew Scott, Ludwig Institute for Cancer Research; and Department of Medicine, University of Melbourne, Austin Hospital, Australia

    • Background: Combined radiation and chemo therapy has proved effective in cancer treatment. The efficacy of combining chemotherapy with monoclonal antibody radioimmunotherapy has been demonstrated in animal studies, however data in humans is lacking. This study aimed to investigate the impact of combining capecitabine chemotherapy with high dose 131I-huA33 monoclonal antibody radioimmunotherapy on the tumour dose of patients with metastatic colorectal carcinoma.
    Methods: Analysis of data was performed by comparing the dosimetry results of a recently completed Phase 1 trial of high dose 131I-huA33 given in combination with oral capecitabine therapy, with data from of a prior 131I-huA33 only therapy study. A total of 34 subjects were analysed 19 receiving combined 131I-huA33/Capecitabine treatment and 15 receiving only therapeutic 131I-huA33.
    Planar whole body tumour dosimetry analysis was performed on all subjects with the mean absorbed tumour dose of a reference lesion being calculated. Statistical analysis including 95% confidence intervals calculations and t-testing for p-value analysis was performed to investigate the significance of results.
    Results: The resultant mean tumour doses for the 2 studies, 131I-huA33 therapy and the combined 131I-huA33/Capecitabine study, were 6.49 + 2.47 Gy/GBq and 5.17 + 2.83 Gy/GBq respectively (P=0.25). Doses to tumour at the 40mCi/m2 dose level ranged from 12.0 - 32.7 Gy and 14.9 - 26.9 Gy respectively (P=0.60).
    Conclusion: Combined capecitabine/131I-huA33 therapy allows for the potential benefits of optimised therapy to be achieved without impacting on 131I-huA33’s tumour uptake and the associated absorbed tumour radiation dose.

    Conference Organiser - ICMS Pty Ltd