For distant metastases from cervical cancer, CT is inferior in the detection of osseous metastases (sensitivity 66%) compared with FDG-PET/CT (sensitivity 96%) [25]. These findings, if applied to vaginal cancer, suggest that CT is a reasonable staging tool for known or suspected tumor recurrence in the abdomen and pelvis, although it is likely inferior to MRI for evaluating local tumor extent, modestly inferior to FDG-PET/CT for nodal metastases, and inferior to FDG-PET/CT for osseous metastases. The use of IV contrast is strongly encouraged when possible, because the improved tissue contrast likely benefits primary tumor evaluation, delineation of lymph nodes from adjacent vessels, and detection of hepatic metastases. No studies have specifically assessed the performance of CT of the abdomen and pelvis without IV contrast for evaluation of known or suspected vaginal cancer recurrence. FDG-PET/CT Skull Base to Mid-Thigh No study has evaluated FDG-PET/CT in a cohort limited to patients with recurrent vaginal cancer. Data on the utility of FDG-PET/CT in this setting is limited to mixed cohorts of patients with various gynecologic malignancies, including vaginal cancer, with cervical squamous cell carcinoma generally comprising the majority of patients. One such cohort of 27 patients with recurrent gynecologic malignancies prior to pelvic exenteration was studied prospectively to compare FDG-PET and CT. FDG-PET was 100% sensitive and 73% specific for identifying extrapelvic metastases, most notably outperforming CT in the detection of pelvic and para-aortic nodal metastases [29]. A retrospective study of 85 patients with recurrent gynecologic malignancies reached similar conclusions, identifying findings suspicious for extraregional recurrence in 28% (24 of 85) of patients by PET versus 9% (8 of 85) of patients by conventional imaging (CT and pelvic MRI), with nodal metastases accounting for many of the discrepancies [30].
Staging and Follow up of Primary Vaginal Cancer. For distant metastases from cervical cancer, CT is inferior in the detection of osseous metastases (sensitivity 66%) compared with FDG-PET/CT (sensitivity 96%) [25]. These findings, if applied to vaginal cancer, suggest that CT is a reasonable staging tool for known or suspected tumor recurrence in the abdomen and pelvis, although it is likely inferior to MRI for evaluating local tumor extent, modestly inferior to FDG-PET/CT for nodal metastases, and inferior to FDG-PET/CT for osseous metastases. The use of IV contrast is strongly encouraged when possible, because the improved tissue contrast likely benefits primary tumor evaluation, delineation of lymph nodes from adjacent vessels, and detection of hepatic metastases. No studies have specifically assessed the performance of CT of the abdomen and pelvis without IV contrast for evaluation of known or suspected vaginal cancer recurrence. FDG-PET/CT Skull Base to Mid-Thigh No study has evaluated FDG-PET/CT in a cohort limited to patients with recurrent vaginal cancer. Data on the utility of FDG-PET/CT in this setting is limited to mixed cohorts of patients with various gynecologic malignancies, including vaginal cancer, with cervical squamous cell carcinoma generally comprising the majority of patients. One such cohort of 27 patients with recurrent gynecologic malignancies prior to pelvic exenteration was studied prospectively to compare FDG-PET and CT. FDG-PET was 100% sensitive and 73% specific for identifying extrapelvic metastases, most notably outperforming CT in the detection of pelvic and para-aortic nodal metastases [29]. A retrospective study of 85 patients with recurrent gynecologic malignancies reached similar conclusions, identifying findings suspicious for extraregional recurrence in 28% (24 of 85) of patients by PET versus 9% (8 of 85) of patients by conventional imaging (CT and pelvic MRI), with nodal metastases accounting for many of the discrepancies [30].