Image-guided Adaptive Radiotherapy in Cervical Cancer.

This paper reviews the conceptual, methodological, and technical innovations underpinning strategies for adaptive target volume selection and risk-adapted dose prescription in cervical cancer. An adaptive target volume concept has been developed which reflects tumor shrinkage at the end of initial chemo-radiation, which serves for an image-guided boost delivered through brachytherapy, with a risk-adapted dose prescription to different gross tumor- and clinical target volumes defined at diagnosis and after 40-50Gy external beam radiotherapy, and adaptation of the treatment technique according to the topography of the tumor after response and adjacent organs at risk. Clinical results of these innovations are presented based on prospective and retrospective multi-center trials (IntErnational study on MRI-based BRachytherapy in locally Advanced CErvical cancer [EMBRACE], retroEMBRACE) with large patient cohorts (n = 1416, n = 731). The potential benefit of applying these strategies and using a specific multi-parametric dose prescription protocol are explored (EMBRACE-II) and overall current and future research strategies are outlined. The challenges of dissemination and implementation of these complex new techniques into clinical practice are discussed.