Effects of 3D image-guided brachytherapy compared to 2D conventional brachytherapy on clinical outcomes in patients with cervical cancer: A systematic review and meta-analyses

PURPOSE: To assess the effects of three-dimensional image-guided brachytherapy (3D BT) compared to bi-dimensional BT (2D BT) on clinical outcomes in patients with cervical cancer. METHODS AND MATERIALS: We searched PubMed/MEDLINE, EMBASE, Scopus, CENTRAL, Web of Science, and LILACS for studies assessing the effects of 3D BT versus 2D BT on clinical outcomes. Two reviewers independently screened retrieved citations, extracted data and assessed risk of bias from eligible studies. Hazard ratios (HR) were calculated from Kaplan-Meier curves considering the number of events, their timing and the followup of censored patients. We conducted meta-analyses of HR using the inverse-variance random-effects method. Risk Difference (RD) for toxicities were pooled using the Mantel-Haenszel random-effects method. We used the GRADE system to rate the certainty of evidence. RESULTS: Twenty observational studies involving 4287 patients were included. The meta analyses assessing the effect of 3D BT versus 2D BT on overall survival resulted in a HR of 0.78 (95%CI 0.62-0.98), HR of 0.75 (95%CI 0.62-0.90) for pelvic disease-free survival, HR of 0.93 (95%CI 0.81-1.06) for metastatic disease-free survival, and HR of 0.77 (95%CI 0.59-0.99) for local control. Grade 3-4 global and gastrointestinal toxicities were, respectively, 9% lower (95%CI 6% to 11%) and 5% lower (95%CI 2% to 8%) in patients receiving 3D BT versus 2D BT. Certainty of evidence was very low for all assessed outcomes. CONCLUSIONS: Our study may suggest a benefit of 3D BT over conventional 2D BT on important clinical outcomes. (c) 2021 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.