Session

Overview: As radiotherapy outcomes continue to improve, there has been a significant increase in demand for re-irradiation for secondary or recurrent cancers. However, re-irradiation remains one of the most challenging areas of radiotherapy, as normal tissue risks arising from combined exposures must be carefully managed. This session will provide a review of clinical-decision making in re-irradiation, including consideration of key knowledge gaps and limitations in current clinical data. This will be followed by a discussion of the biological modelling of re-irradiation, including the calculation of combined equivalent doses in conventional and hypofractionated therapy, the use of time- and recovery-factors, and the potential role of systemic conditions beyond the irradiated organs on patient responses.