Background: Imaging modalities including computed tomography (CT) scan, magnetic resonance imaging (MRI) and positron emission tomography (PET) are important diagnostic tools in gynecological malignancies. Clinicians usually underestimate PET scan in diagnostic approaches for gynecology cancer patients. In this study, PET scan results are compared with MRI and CT scan for restaging of gynecological malignancies to evaluate possible changes in treatment strategy. Materials and methods: In this cross-sectional study, 365 cases referred to a training hospital in Tehran-Iran between 2014 and 2017 for restaging of gynecological cancers including ovarian, cervical and uterine cancers were enrolled. The results of PET scan were compared with MRI and CT scan for added value of PET scan over CT scan or MRI to demonstrate evidence of under or over diagnosed new, residual or recurrent disease. Results: The CT scan and MRI results demonstrated positive findings in 45.5% and were unremarkable in 9.6% of patients. Applicability of PET scan for increasing the diagnostic accuracy for detection of peritoneal seeding (P=0.0001), lung metastasis (P=0.001), abdominal metastasis (P=0.0001), abdominal lymphadenopathy (P=0.0001), mediastinal/hilar lymphadenopathy (P=0.005), and local recurrence (P=0.028) were significant. For ovarian, cervical, endocervical and uterine cancers; there was diagnostic usefulness of 93.5%, 89.8%, 85.2%, and 82.2%, respectively. Conclusion: According to our study PET scan is an adjunctive diagnostic tool, helpful for restaging of gynecological malignancies more specifically in cases with peritoneal seeding, lung and abdominal metastases, mediastinal/hilar and abdominal lymphadenopathies and local recurrence. The applicability of PET scan is higher in ovarian and cervical malignancies.
