Published online Oct 10, 2014. doi: 10.5306/wjco.v5.i4.764
Revised: February 28, 2014
Accepted: April 3, 2014
Published online: October 10, 2014
Brachytherapy forms an integral part of the radiation therapy in cancer cervix. The dose prescription for intracavitary brachytherapy (ICBT) in cancer cervix is based on Tod and Meredith’s point A and has been in practice since 1938. This was proposed at a time when accessibility to imaging technology and dose computation facilities was limited. The concept has been in practice worldwide for more than half a century and has been the fulcrum of all ICBT treatments, strategies and outcome measures. The method is simple and can be adapted by all centres practicing ICBT in cancer cervix. However, with the widespread availability of imaging techniques, clinical use of different dose-rates, availability of a host of applicators fabricated with image compatible materials, radiobiological implications of dose equivalence and its impact on tumour and organs at risk; more and more weight is being laid down on individualised image based brachytherapy. Thus, computed tomography, magnetic-resonance imaging and even positron emission computerized tomography along with brachytherapy treatment planning system are being increasingly adopted with promising outcomes. The present article reviews the evolution of dose prescription concepts in ICBT in cancer cervix and brings forward the need for image based brachytherapy to evaluate clinical outcomes. As is evident, a gradual transition from “point” based brachytherapy to “profile” based image guided brachytherapy is gaining widespread acceptance for dose prescription, reporting and outcome evaluation in the clinical practice of ICBT in cancer cervix.
Core tip: Traditionally, intracavitary brachytherapy in cancer cervix is based on dose prescription at point A. However, with the availability of computed tomography-magnetic resonance imaging compatible applicators, various imaging techniques, treatment planning systems for dose computations and evaluation, there is a gradual shift towards image based brachytherapy. The article reviews the evolution of dose prescription concepts from “point” to “image” based brachytherapy in the current clinical practice of intracavitary brachytherapy of cancer cervix. This could enable prescribing doses to conform the target and avoid normal structures based on individualized applicator geometry, tumour architecture and anatomy of the organs at risk, thereby improving the therapeutic outcome.