Pulmonary metastases appear to occur slightly more frequently as a site of recurrent disease, with one large study of recurrent cervical cancer indicating an overall incidence of 13%, and the lungs representing the only site of recurrence in 6% of cases [15]. Moreover, the lungs can uncommonly represent a site of distant disease that newly arises following definitive chemoradiation for disease that was initially locoregional [41]. In studies evaluating pulmonary metastases from cervical cancer, chest CT was the most frequent diagnostic modality employed, with the vast majority of patients asymptomatic at the time of imaging [16,17]. These findings support the use of chest CT with or without IV contrast in the early posttreatment evaluation of cervical cancer, as endorsed by the NCCN guidelines, and suggest that a similar strategy would be useful for vaginal cancer. CT Abdomen and Pelvis For detection of residual primary tumor after chemoradiation, CT alone is likely inferior compared with FDG- PET/CT and pelvic MRI based on extrapolation from data on comparative imaging performance in the pretreatment evaluation of cervical cancer [21,44]. CT lacks the tissue contrast of MRI and the metabolic data of FDG-PET, both of which are useful in deciphering posttreatment changes from residual disease. Because CT relies primarily on size criteria for nodal evaluation, it has limitations similar to MRI with respect to sensitivity and specificity for nodal metastases. Therefore, although CT may depict size regression of nodal metastases following therapy, it is likely at least modestly inferior for detecting new or residual disease in subcentimeter lymph nodes compared with FDG- PET/CT [22,23,29,30].
Staging and Follow up of Primary Vaginal Cancer. Pulmonary metastases appear to occur slightly more frequently as a site of recurrent disease, with one large study of recurrent cervical cancer indicating an overall incidence of 13%, and the lungs representing the only site of recurrence in 6% of cases [15]. Moreover, the lungs can uncommonly represent a site of distant disease that newly arises following definitive chemoradiation for disease that was initially locoregional [41]. In studies evaluating pulmonary metastases from cervical cancer, chest CT was the most frequent diagnostic modality employed, with the vast majority of patients asymptomatic at the time of imaging [16,17]. These findings support the use of chest CT with or without IV contrast in the early posttreatment evaluation of cervical cancer, as endorsed by the NCCN guidelines, and suggest that a similar strategy would be useful for vaginal cancer. CT Abdomen and Pelvis For detection of residual primary tumor after chemoradiation, CT alone is likely inferior compared with FDG- PET/CT and pelvic MRI based on extrapolation from data on comparative imaging performance in the pretreatment evaluation of cervical cancer [21,44]. CT lacks the tissue contrast of MRI and the metabolic data of FDG-PET, both of which are useful in deciphering posttreatment changes from residual disease. Because CT relies primarily on size criteria for nodal evaluation, it has limitations similar to MRI with respect to sensitivity and specificity for nodal metastases. Therefore, although CT may depict size regression of nodal metastases following therapy, it is likely at least modestly inferior for detecting new or residual disease in subcentimeter lymph nodes compared with FDG- PET/CT [22,23,29,30].