Session Item

Personalised radiotherapy is a term that can be used to describe how the radiation dose, fractionation, target volume, margins and/or the use of concomitant systemic treatment or radiosensitising agents might be individualised based on knowledge of tumour biology or patient characteristics.  The aim of tailoring radiotherapy in such a way, or of prospectively adapting individual treatment plans based on biomarkers of response or normal tissue effects, is to improve the therapeutic ratio through improved disease control and/or reduced side effects.  Methodology for the clinical evaluation of personalised radiotherapy hinges on the magnitude of the potential benefits in either (or both) of these domains and of the proportion of patients receiving personalised treatment.
Strategies that result in minor changes to the treatment plan for a very small numbers of patients may not lead to cost effective benefit at a population level.  Where personalisation is hypothesised to lead to moderate benefits, randomised controlled trials utilising reliable and patient prioritised endpoints are needed drive practice change; where large and low cost benefits are anticipated the level of evidence required may be less but are radiobiological modelling or dosimetric planning studies sufficient?
Where adaption is aimed at reducing toxicity we need to consider how best to measure this – through clinician reporting of radiation side effects or patient reporting of the impact of any side effects on their quality of life; and whether there is a need to formally demonstrate non-inferiority of disease control in a randomised controlled trial.  Where radiation is combined with systemic therapy or radiosensitising agents to enhance efficacy, care must be given to assessing not just radiation related side effects but the impact of the combination therapy.  Methodological evaluation of response or predictive biomarkers to guide treatment requires biomarker-stratified or biomarker-strategy designs.
This talk will expand on some of the methodological issues related to evaluating personalised radiotherapy. [It is likely to raise more questions than answers].