The HeartSpare Plus 1B Trial: A Randomised Phase II Trial Comparing the Resource Impact, Acute Toxicity and Feasibility of Different Pan-lymph Node Radiotherapy Techniques for Breast Cancer Patients

Following publication of results of two large randomised clinical trials, pan-lymph node radiotherapy (pan-LN RT) (including treatment of the internal mammary chain) is set to become standard treatment in patients with lymph-node positive breast cancer. Traditional pan-LN RT techniques deliver high radiation doses to the heart and lungs which can cause long-term side-effects in women many years after their treatment. Modern techniques including breath-holding and volumetric-modulated arc therapy (VMAT) can reduce doses to heart and lungs but the investigators do not yet know which technique(s) are best in terms of resource costs, short to medium-term side-effects, and day to day accuracy. This study will compare the time taken to deliver pan-LN RT using breath-holding versus VMAT and will collect side-effect data up to one year following treatment as well as modelling long-term cardiac risks based on heart doses delivered. The results of the main study will help guide clinicians and departments in selecting the best pan-LN RT techniques for their patients. A parallel study will evaluate the combination of breath-hold and VMAT using a machine-based technique called the active-breathing controlled (ABC) device against a more simple voluntary breath-hold technique were patients simply take a breath in and hold it for up to 20 seconds at a time. These techniques will be compared in terms of their day-to-day accuracy. If the simpler technique proves as accurate as the ABC-technique, this will establish the simpler technique as a less resource-intensive standard of care adoptable by other radiotherapy departments.