Early Detection of Recurrent Ovarian Cancer in Patients with Low-Level Increases in Serum CA-125 Levels by 2-[F-18]Fluoro-2-Deoxy-D-Glucose-Positron Emission Tomography/Computed Tomography

Purpose: Serum CA-125 has been shown to be a sensitive tumor marker of recurrent ovarian cancer. The goal of this study was to evaluate the use of 2-[F-18]fluoro-2-deoxy-d-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the early detection of recurrent ovarian cancer in patients with low-level increases in serum CA-125 levels. Methods: Patients who demonstrated a normalization of serum CA-125 levels after complete remission of ovarian cancer were recruited for this study. FDG-PET/CT was performed to evaluate serum CA-125 levels >= 35 U/mL (Group 1) or progressive low-level increases in the levels of serum CA-125 (Group 2). The results were analyzed based on pathology, disease progression, and/or clinical follow-up. Results: Twenty-seven (27) consecutive patients consented to the aforementioned criteria (n = 16 in Group 1 and n = 11 in Group 2). In Group 1, of the 16 patients, 15 had a proven tumor recurrence, and the remaining 1 had a second primary cancer with no evidence of recurrent ovarian lesions. In Group 2, all 11 patients had recurrent tumors. The use of FDG-PET/CT allowed the detection of recurrences in 25 patients and a second primary cancer in 1 patient, which included all of the patients in Group 1 and 10 of the 11 patients in Group 2. The detection rate of FDG-PET/CT for recurrent ovarian cancer was 100% in Group 1 and 90.9% in Group 2 (15/15 vs. 10/11, p = 0.423). FDG-PET/CT changed the intended management in 14 (53.8%) of the patients, which included 4 cases in Group 1 and 10 cases in Group 2. Conclusions: FDG-PET/CT has the ability to detect recurrent ovarian cancer and second primary tumors in patients with increased levels of serum CA-125. FDG-PET/CT affects the clinical management by localizing recurrent lesions and creating a specific treatment plan for each patient, especially patients who demonstrate a low-level increase in serum CA-125 levels.