Factors influencing the outcome of radiotherapy in malignant mesothelioma of the pleura - A single-institution experience with 189 patients

Purpose: To determine the factors influencing the response to palliative radiotherapy (RT) in malignant mesothelioma of the pleura (MM). Methods and Materials: A retrospective review was conducted of the records of all patients with mesothelioma who were referred to our institution between 1979 and 1996. A total of 227 RT series were administered to 189 patients with MM. Of these, 21 patients with chest wall nodules also received concomitant local hyperthermia. Results: The median survival was 5 months from the start of RT and only 17% of patients were alive at 1 year after treatment. Chest pain and painful chest wall metastases were the main indications for RT. A higher local response rate was seen for patients treated with a 4-Gy per fraction scheme, vs. those receiving fractions of less than 4 Gy (50% vs. 39%). Pain recurrence occurred predominantly within the previous RT field, and pain recurred after a median of 69 days (range 32-363) in the group treated using 4-Gy fractions. When compared with a matched group, patients treated with combined RT and hyperthermia had higher response rates and fewer in-field recurrences. Conclusions: RT provides local palliation in at least 50% of patients with MM who were treated using a 4-Gy/fraction scheme to a median dose of 36 Gy. The low response rates with RT alone suggest that combined RT and local hyperthermia should be further evaluated in MM.