Evolution of Intracavitary Brachytherapy in the Treatment of Cervical Cancer

Abstract

The evolution of intracavitary brachytherapy in the treatment of cervical cancer spans over 120 years. The purpose of this review is to understand how the discovery of radium paved the way to the current standard of care; the image-guided adaptive brachytherapy. Materials and Methods:A literature search was done to identify the important milestones in the evolution. The terminologies used for the search were "history", "brachytherapy", "radium", "dosimetric systems" and "image-guided adaptive brachytherapy" (IGABT).The information gathered was organized in chronological order and the key milestones were identified. Results:The origin of brachytherapy can be tracked down to the discovery of radioactivity by Sir Henry Becquerel, followed by the invention of radium by the Curies' in the late 19 th century. In the early 20 th century, various dosimetric systems evolved. Among these systems, the Manchester system prescribing to point A became popular and was widely in practice for many decades. The deficiencies of the point A prescription model were brought to light with the advances in soft tissue imaging in the late 20 th century. Imaging helped in prescribing to the actual tumor volume and to generate dose-volume histograms to achieve better target coverage while reducing the dose to the organs at risk. The IGABT started with computed tomography and was further enhanced by magnetic resonance imaging (MRI) due to better anatomical delineation of the pelvis anatomy. Hence MRI based adaptive brachytherapy became the gold standard and has been proven to be safe and effective while significantly reduced toxicity. As cervix cancer is most prevalent in low resource regions, ultrasound scanning has been identified as a reasonable substitute for MRI. Conclusion:Intracavitary brachytherapy in the treatment of cervical cancer has developed over the last 120 years and has made tremendous advances in the last 20 years.