ABSTRACT
OBJECTIVE: This study is to investigate whether Positron Emission Tomography (PET) is useful for determining pathologic complete response in patients with ovarian carcinoma who had a clinical complete response after primary treatment. METHODS: FDG-PET scans were performed in 10 patients with advanced ovarian cancer (4 patients with stage IIC, 6 patients with IIIC), who showed complete response with cytoreductive surgery and 6 cycles of post-operative adjuvant Cisplatin-based combination chemotherapy. FDG-PET scan was obtained with GE Advance Scanner, beginning at 50 minutes after injection of 370-555 MBq (10-15 mCi) of 18F FDG. Uptakes exceeding 3.5 SUV (Standardized Uptake Value) or larger than surrounding tissue were determined as a positive findings. Second-look laparotomy was undertaken within median 4 days after FDG-PET scanning. RESULTS: The mean age of the patients was 45 years and serous cystadenocarcinoma was most common histologic type. None showed active lesion in pelvis or abdomen with FDG-PET scan (SUV: >3.5 kg/ml), however, 5 patients (50%) showed residual tumors on multiple biopsy during second look operation. One patient showed positive lesion in lung on FDG-PET scan, which was confirmed to have metastatic lesion. CONCLUSION: FDG-PET scan is not useful for detection of small ovarian cancer lesions in pelvis and abdomen and cannot substitute for second-look operation to determine pathologic complete response.