High-dose palliative radiotherapy for malignant pleural mesothelioma

High-dose radiotherapy to the hemithorax for patients with malignant pleural mesothelioma is a controversial treatment. Between 2003 and 2013 our institution had a policy of giving hemithoracic radiotherapy to at least 45 Gy. This retrospective study reports survival, progression and toxicity associated with this policy.

Seventy-one patients with pleural mesothelioma were irradiated with doses of 45-60 Gy. Conformal radiotherapy (3D-CRT) to the lower hemithorax was used for 17 and intensity-modulated radiotherapy (IMRT) to the whole hemithorax for 54 patients. All patients have been followed up for at least 2 years from commencement of radiotherapy.

Sixty-four patients (90%) completed planned radiotherapy and seven stopped early, usually due to progressive disease. Median overall survival was 9.5 months (95% CI: 7.7-12.4) and median progression-free survival was 4.9 months (95% CI: 4.4-5.8). Eighty-seven per cent of patients progressed or died within 2 years: 25% in-field, 49% outside the RT field and 13% died without progression. Severe toxicity (grade 3-5) was observed in 53% of 3D-CRT and 78% of IMRT patients, most commonly pulmonary fibrosis 27%, radiation dermatitis 18%, dyspnoea 11%, GGT increased 11%, pneumonitis 10%, pleuritic pain 8% and fatigue 8%. There were two, possibly three, treatment-related deaths.

High-dose radiotherapy to the hemithorax caused significant toxicity to most patients with no improvement in survival. Lower doses of radiotherapy to limited volumes may be useful for palliative purposes.