The SYSTEMS study, published in 2015, was the first prospective study to use validated outcome measures to assess pain responses to radiotherapy in malignant pleural mesothelioma (MPM). This phase II, multicentre study demonstrated that standard dose palliative radiotherapy (20Gy in 5 fractions delivered over 1 week) produced a clinically significant improvement in pain for one third of patients with minimal toxicity. Link to original paper here.
SYSTEMS-2 is a multicentre, phase II, randomised trial of radiotherapy dose escalation for pain control in MPM, comparing 20Gy in 5 fractions delivered over 1 week with a dose-escalated regime of 36Gy in 6 fractions over 2 weeks. The primary endpoint is pain control at week 5 as assessed by the Brief Pain Inventory.