Comparison of positron emission tomography/computed tomography and magnetic resonance imaging for posttherapy evaluation in patients with advanced cervical cancer receiving definitive concurrent chemoradiotherapy.

Purpose: Our purpose was to assess the diagnostic performance of positron emission tomography/computed tomography (PET/CT) and pelvic/abdominal magnetic resonance imaging (MRI) after concurrent chemoradiotherapy (CCRT) for posttherapy evaluation in patients with advanced cervical cancer.

Methods: Patients with cervical squamous cell carcinoma, either with advanced FIGO stage or with positive pelvic or para-aortic lymph node (PALN), received PET/CT using [F]fluorodeoxyglucose and MRI including diffusion-weighted imaging between 2 and 3 months after CCRT completion. PET/CT were interpreted independently by two nuclear medicine physicians and MRI by two radiologists using the same scoring system. Active residual tumor was proven by pathological confirmation or disease progression on imaging studies within one year after CCRT and the disease regions were classified as local, regional, PALN, or distant. Patient-based and region-based comparison was performed using the receiver operating characteristic curve analysis.

Results: The study included 55 patients and 15 (27%) patients had active residual tumor. The diagnostic performance of PET/CT is significantly superior to that of MRI in patient-based analysis (P = 0.025) and in the detection of local (P = 0.045) and regional (P = 0.014) disease. The patient-based sensitivity, specificity, and accuracy of PET/CT are 60%, 100%, and 89% while those of MRI are 27%, 100%, and 80%.

Conclusions: PET/CT is superior to MRI for posttherapy evaluation in patients with advanced cervical cancer 2-3 months after definitive CCRT, mainly for the detection of residual local and regional disease. Patients with negative or equivocal results should be followed up regularly due to suboptimal sensitivities of imaging.