The Hyperbaric OxygeN therapy in brEast cancer patient with late radiation toxicitY (HONEY) trial is a randomized controlled trial with a primary objective to compare the effect of hyperbaric oxygen therapy with usual care in breast cancer patients with late radiation toxicity in terms of pain, physical functioning and quality of life.

The HONEY trial follows the Trials within Cohorts (TwiCS) design within the Utrecht cohort for Multiple BREast cancer intervention studies and Long-term evaLuAtion (UMBRELLA) cohort consent for participation is asked to all new patients from the radiotherapy department in the UMC Utrecht. Upon inclusion all participants may consent for: collection of their clinical data, patient reported outcome measurements by means of questionnaires (i.e. quality of life, cosmetic evaluation, fatigue, workability) and future randomization.

In the UMBRELLA study 120 patients will be selected and randomized (2:1) to receive hyperbaric oxygen therapy or usual care. In accordance with the TwiCS, only participants in the hyperbaric oxygen group will be informed about the study. After consent, participants in the hyperbaric oxygen group will be referred for standard hyperbaric oxygen therapy.