Is F18 FDG PET-CT an Authoritative Investigation as Compared to Other Conventional Imaging (CECT) Modality in Treated Cervical Cancer Patients?

Objectives To evaluate the diagnostic performance of contrast-enhanced F18 FDG PET-CT with conventional modality (contrast-enhanced computed tomography) in restaging of cervical carcinoma. Study Design A retrospective analysis of histopathological proven patients of carcinoma cervix (n = 386; age range 32-82 years; mean age 51.4 years) between April 2017 and July 2022 was done. All the patients were treated either in combination or alone with surgery, radiotherapy or chemotherapy. The patients were referred for F18 FDG PET-CT on the basis of clinical and imaging suspicion of residual or recurrent disease and for post-therapy monitoring. Histopathological examination and clinical or imaging follow-up were taken as gold standard. Results Of 386 patients, underwent PET-CT examination for post-therapy monitoring. F18 FDG PET-CT detected abnormal FDG uptake in 258 patients. Uptake at the primary site was detected in 112/258 (43.41%) patients, and only regional pelvic lymph nodes and distant metastatic lesions were in 18/258 (similar to 6.96%) and 128/258 (49.4%) patients, respectively. On lesion-based analyses, distant metastases, lymph nodes, lung, liver and skeleton were noted in 128, 50, 18 and 30 patients respectively, either isolated or combined. Fourteen patients had distant metastases at rare sites including kidney, muscle, ascites, pleural effusion and gut (4, 4, 2, 2, 2). Additionally, metachronous primaries were also detected in 18 patients and confirmed on histopathology (lung-6, pharynx-4, breast-4, lymphoma-2 and rectum-2). After a median follow-up period of 30 months (+/_; SD 20.8), 226 patients having residual or recurrence disease and FDG PET-CT had the sensitivity, specificity, PPV, NPV and accuracy as 89.38, 65, 78.29, 81.25 and 80%, respectively, while conventional imaging (CI) had the sensitivity, specificity, PPV, NPV and accuracy of 66.42, 40.68, 71.77, 34.78 and 70%, respectively. On ROC curve analysis, SUVmax > 4.4 had sensitivity and specificity 78.8 and 83.7%, respectively, for lesion detection on F18 FDG PET-CT. There was a significant correlation between SUVmax and patient outcome (r = similar to 0.0585). Conclusions This study concluded that F18 FDG PET-CT has high diagnostic accuracy as compared to conventional imaging for detection of suspected residual/recurrent disease in cervical cancer patients and also useful in detection of additional metachronous second primary.