Re-evaluating the role of palliative radiotherapy in malignant pleural mesothelioma.

Purpose: To determine the objective response rate of malignant pleural mesothelioma (MPM) to short course radiation therapy.

Methods: We reviewed the cases of 54 patients with advanced MPM who were treated with palliative radiotherapy according to a standardised institutional policy. Pre- and post-treatment computed tomography scans were used to assess response.

Results: Fifty-seven percent of patients reported some improvement in their symptoms following radiotherapy. The radiology response rate was 43% (22 patients had a partial response and 1 patient a complete response). Response to treatment was correlated with the European Organisation for Research and Treatment of Cancer (EORTC) prognostic index (p=0.001), performance status (p=0.02) and histological subtype (p=0.04). In the EORTC good prognosis group 56% of patients responded, compared with only 7% in the poor prognosis group (p=0.001). The median survivals from diagnosis and from the start of radiotherapy were 11.3 months and 5.2 months, respectively. Survival following treatment was correlated with the EORTC prognostic index (p<0.001), histological subtype (p<0.001), performance status (p=0.001), treatment response (p=0.002) and haemoglobin level (0.02). The EORTC good and poor prognostic groups had survivals of 7.1 and 2.1 months, respectively (p<0.001). Neither tumour volume nor stage were associated with prognosis.

Conclusions: Palliative radiotherapy produces a response rate in MPM that is equivalent to chemotherapy. The EORTC prognostic index can be used to select patients who are most likely to benefit from this treatment.