The Potential Value of MRI in External-Beam Radiotherapy for Cervical Cancer

Area of Science:

• Radiation oncology
• Medical imaging
• Gynecologic oncology

Background:

• Standard cervical cancer treatment involves chemoradiotherapy and MRI-guided brachytherapy, achieving good local control but with high rates of late toxicity (11% grade ≥3).
• Inter-fraction motion of the cervix and uterus during external-beam radiotherapy necessitates large margins, increasing radiation exposure to organs at risk and contributing to toxicity.
• Current image-guided radiotherapy techniques struggle with unpredictable, random motion, highlighting the need for advanced solutions.

Purpose of the Study:

• To review the potential value of magnetic resonance imaging (MRI) in external-beam radiotherapy for cervical cancer, particularly with the advent of integrated MRI linear accelerators.
• To discuss current strategies for managing pelvic organ motion and the potential of online adaptive radiotherapy.
• To explore the impact of MRI on tumor delineation and the delivery of stereotactic ablative body radiotherapy (SABR), as well as the challenges of using multiparametric MRI.

Main Methods:

• Review of existing literature on image-guided radiotherapy (IGRT) techniques for managing pelvic organ motion in cervical cancer.
• Discussion of the role of MRI in external-beam radiotherapy, including integrated MRI-linac systems.
• Analysis of MRI's application in tumor delineation, stereotactic ablative body radiotherapy (SABR), and multiparametric MRI for radiotherapy guidance.

Main Results:

• MRI offers potential for improved tumor delineation and reduced margins in cervical cancer radiotherapy, thereby decreasing radiation dose to organs at risk.
• Online adaptive radiotherapy guided by MRI may help manage inter-fraction motion more effectively than current IGRT methods.
• The integration of MRI in radiotherapy delivery, including SABR, presents opportunities but also challenges, particularly with multiparametric MRI utilization.

Conclusions:

• Integrated MRI-linac technology holds significant promise for enhancing the precision and safety of cervical cancer radiotherapy.
• MRI-guided adaptive radiotherapy has the potential to reduce toxicity while improving local control by accurately accounting for organ motion.
• Further research and development are needed to overcome challenges associated with multiparametric MRI and its clinical implementation in radiotherapy.