Paraaortic Lymph Nodal Staging & Evaluation of Treatment Outcome by 18-Fluorodeoxyglucose PET (Positron Emission Tomography) in Advanced Cervical Cancer: Final Results of a Prospective Observational Cohort Study

Purpose The purpose of this study was to evaluate the use of 18-fluorodeoxyglucose positron emission tomography (PET) in detecting paraaortic nodes and for response assessment/follow-up in advanced cervical cancer. Methods From 2005 to 2008, 96 patients with stage IIB & IIIB cervical cancer were included in the study. PET/CT (PET/computed tomography) was done at baseline and post-treatment at 6, 12, 18 and 24 months of follow-up. Extended-field radiotherapy was given to the patients with positive paraaortic node in CT scan. Results Nineteen patients (19.8%) received extended-field radiotherapy in view of positive paraaortic node in CT scan. Six patients (6.25%) had CT-negative PET-positive paraaortic node and two patients had CT positive PET-negative paraaortic node. Median follow-up was 80 months (interquartile range 56-106 months). The 5 year disease-free survival of patients with CT & PET-negative paraaortic node, CT-negative PET-positive paraaortic node and CT positive paraaortic node were 71%, 60% and 33%, respectively (p = 0.002). The 5-year overall survival of patients with complete metabolic response (n = 66), partial metabolic response (n = 9) and progressive metabolic disease (n = 21) was 84.8%, 26.7% and 17.1%, respectively (p < 0.001). Among the patients with relapse detected in PET/CT (n = 28), 18 had PET done at scheduled follow-up, but with no significant difference in post-relapse survival (median: 10.5 vs 7 months; p = 0.164). Out of 14 relapses detected at 6-month PET/CT, 11 included nodal/systemic relapse. Fifty percent of patients with >= 2cm node had persistent nodal disease at 6 months PET-CT. Conclusion PET-CT at baseline resulted in a small incremental benefit in detecting avid paraaortic nodes. Patients with routine follow up PET detected relapse but did not have significantly improved post relapse survivals. Further prospective studies with PET-CT response assessment in node positive patients and its impact on salvage treatment is warranted.