Positron Emission Tomography for Evaluating Para-aortic Nodal Metastasis in Locally Advanced Cervical Cancer Before Surgical Staging: A Surgicopathologic Study

Abstract

PURPOSE: Positron emission tomographic (PET) scanning provides a novel means of imaging malignancies. This prospective study was undertaken to evaluate PET scanning in detecting para-aortic nodal metastasis in patients with locally advanced cervical carcinoma and no evidence of extrapelvic disease before planned surgical staging lymphadenectomy. MATERIALS AND METHODS: After 20 mCi of 2-[18 F]fluoro-2-deoxy-d-glucose (FDG) were administered intravenously, the abdomen and pelvis were scanned. Continuous bladder irrigation was used to reduce artifact. Patients were classified by the presence or absence of FDG uptake in the primary tumor and in pelvic or para-aortic nodes. Para-aortic node metastases were classified as present or absent according to a standardized staging procedure. Pelvic node metastases were similarly classified in a subset of patients who underwent pelvic node resection. RESULTS: Thirty-two patients with stage IIB (n = 6), IIIB (n = 24), and IVA (n = 2) tumors were studied. Fluorodeoxyglucose was taken up by 91% of the cervical tumors. Six of eight patients with positive para-aortic node metastasis had PET scan evidence of para-aortic nodal metastasis. One of the two false-negatives had only one microscopic focus of metastatic cancer. In the para-aortic nodes, PET scanning had a sensitivity of 75%, a specificity of 92%, a positive predictive value of 75%, and a negative predictive value of 92%. Fluorodeoxyglucose para-aortic nodal uptake conferred a relative risk of 9.0 (95% confidence interval, 2.3 to 36.0) for para-aortic nodal metastasis. All 10 of 17 patients with metastasis were predicted by PET scanning (P < .001); five of these patients had abnormalities on computed tomographic scans. CONCLUSION: Cervical cancers have a high avidity for FDG. The use of PET-FDG scanning accurately predicts both the presence and absence of pelvic and para-aortic nodal metastatic disease.