A non-randomised phase II study suggested a therapeutic effect of hyperbaric oxygen (HBO) therapy on arm lymphoedema following adjuvant radiotherapy for early breast cancer, justifying further investigation in a randomised trial. Fifty-eight patients with ≥ 15% increase in arm volume after supraclavicular ± axillary radiotherapy (axillary surgery in 52/58 patients) were randomised in a 2:1 ratio to HBO (n=38) or to best standard care (n=20). The HBO group breathed 100% oxygen at 2.4 atmospheres absolute for 100 min on 30 occasions over 6 weeks. Primary endpoint was ipsilateral limb volume expressed as a percentage of contralateral limb volume. Secondary endpoints included fractional removal rate of radioisotopic tracer from the arm, extracellular water content, patient self-assessments and UK SF-36 Health Survey Questionnaire. Of 53/58 (91.4%) patients with baseline assessments, 46 had 12-month assessments (86.8%). Median volume of ipsilateral limb (relative to contralateral) at baseline was 133.5% (IQR 126.0-152.3%) in the control group, and 135.5% (IQR 126.5-146.0%) in the treatment group. Twelve months after baseline the median (IQR) volume of the ipsilateral limb was 131.2% (IQR 122.7-151.5%) in the control group and 133.5% (IQR 122.3-144.9%) in the treatment group. Results for the secondary endpoints were similar between randomised groups. No evidence has been found of a beneficial effect of HBO in the treatment of arm lymphoedema following primary surgery and adjuvant radiotherapy for early breast cancer.

Gothard, Haviland, Bryson, Laden, Glover, Harrison, Woods, Cook, (2010). Randomised phase II trial of hyperbaric oxygen therapy in patients with chronic arm lymphoedema after radiotherapy for cancer. Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, 2010 Oct;97(1):101-7. https://www.ncbi.nlm.nih.gov/pubmed/20605648