Image-guided adaptive brachytherapy for cancer of the cervix: current status and future directions

Abstract Brachytherapy (BT) is an excellent ablative treatment modality capable of delivering extremely high radiation doses precisely to the tumor. Nevertheless, despite its significant potential, the conventional two-dimensional intracavitary BT often faces various challenges, such as inaccurate targeting of the tumor and excessive irradiation of adjacent organs, which can lead to reduced tumor control and increased radiotoxic toxicities, thereby limiting its widespread clinical adoption and implementation. The emergence of four-dimensional image-guided adaptive BT, complemented by interstitial intercalation as well as three-dimensional (3D)-printed patient-specific applicators and implant templates, has brought about a highly individualized, precise, conformal, and tissue-preserving approach to BT. These advanced techniques enhance the accuracy of BT, ensuring that the dose is concentrated within the tumor while rapidly decreasing outside the target. As a result, image-guided adaptive BT can be effectively utilized in multiple tumor types. Moreover, magnetic resonance imaging (MRI) is widely recognized as the most optimal guiding imaging modality for distinguishing between malignant and healthy tissues in BT. However, the clinical application of MRI in BT is currently hindered by challenges related to MRI-compatible applicators and interstitial needles, which require further innovation to enable more extensive utilization. Future developments in BT are expected to focus on personalized dose optimization strategies and dose-guided BT strategies. Additionally, achieving consensus among medical professionals and driving technological innovations to overcome the limitations of current imaging modalities will be crucial for the continuous evolution of BT.