ASSESSMENT OF OVARIAN CANCER BY PET USING F-18-FDG

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Positron Emission Tomography (PET) using F-18-FDG offers the opportunity to assess the extent of ovarian cancer throughout the abdominopelvic cavity for initial staging, and should be most useful as a routine follow-up test for possible recurrent tumor. Dynamic F-18-FDG PET studies were done in 20 patients at the time of initial diagnosis and staging or when recurrent tumor was suspected. Pet results were compared to Computed Tomography (CT) and surgical findings. Those preliminary data suggest for PET a 91% sensitivity, 75 % specificity and a positive predictive accuracy of 86%; for CT, sensitivity and specificity were 83.03% and 50% respectively. The data also indicate that dynamic data acquisition and time activity curve analysis enhance the diagnostic potential of F-18-FDG PET studies of the pelvis and abdomen. The long-term objective of this project is to validate the sensitivity and accuracy of F-18-FDG in localizing 1 ovarian cancer and metastatic abdominopelvic tumor activity for initial staging, monitoring of treatment, detection of recurrent tumor and guided biopsies. Specific aims are: (1) to further substantiate the high predictive accuracy of F- 18-FDG PET; (20 to determine the limitations of spatial resolution of the technique; (3) to correlate dynamic metabolic PET information with tumor nuclear grade and DNA flow cytometry proliferation indices; (40 to develop a method of parametrically imaging the slopes (accumulation rates) of the FDG uptake curves rather than the summation of accumulated activity (counts/pixel/sec), and (50 to determine whether F-18-FDG PET could assist in evaluating treatment response. Patients with suspected ovarian cancer will be selected for this study. They will have a complete workup for ovarian cancer according to a standard ACS guidelines. Dynamic F-18-FDG PET scans of the pelvis and abdomen and static "whole body' scans of the torso will be done prior to biopsy/hysterectomy, in mid-cycle of chemo- and/or radiation therapy, and at time of suspected recurrent tumor. CT and MRI scans will be obtained concomitantly. PET data analysis will include calculation of standardized uptake values (SUVs), time activity curve (TAC) and graphic Patlak analysis. Each patient will be treated by appropriate measures, including biopsy and/or surgery, combined with radiation therapy or chemotherapy. Tumor recurrence (proven by biopsy/histology) and patient survival are the standard against which the predictive value of F-18-FDG PET and flow cytometry will be measured.