Effect of hemithorax irradiation alone or combined with doxorubicin and cyclophosphamide in 47 pleural mesotheliomas: a nonrandomized phase II study.

In order to assess the value of radiotherapy in the treatment of pleural mesotheliomas, we studied tumour response and survival after hemithorax irradiation alone (RT), or radiotherapy combined with doxorubicin and cyclophosphamide chemotherapy (RTCT). Forty seven patients with pleural mesotheliomas received irradiation of the diseased hemithorax at 8 MV (megavolt) photons to a total dose of 40 Gy, administered in 20 daily fractions of 2 Gy for 5 days a week. One month after RT, patients aged < or = 70 yrs with a good performance status were offered supplementary chemotherapy (CT) with doxorubicin 30 mg.m-2 body surface on Day 1 and Day 8, combined with cyclophosphamide 600 mg.m-2 on Day 1, in cycles of 21 days. Tumour response was evaluated by computed axial tomography (CAT) before and 1 month after RT and/or CT. Only 3 of the 47 (95% confidence interval (95% CI)-0.6-13%) irradiated tumours responded with a partial response (PR). In 31 patients treated with RT alone, one PR was observed; whereas, in the combined treatment group, 2 out of 16 responded with PR to RT. CT with doxorubicin and cyclophosphamide induced only 2 out of 16 PRs (95% CI -3.4-28.4%), and the combined treatment consisting of RT followed by CT induced 2 out of 16 PRs. The median survival following the initiation of RT was 7 months in all patients (n = 47), 6 months in the RT group (n = 31), and 13 months in the combined RTCT group (n = 16). Chest pain, performance status and body weight were not favourably affected by the radiotherapy. We conclude that hemithorax irradiation of pleural mesotheliomas with a moderately high dose is not useful, since it produces no improvement in chest pain, few objective tumour responses and no prolongation of survival.