Hemithoracic IMPRINT Safe for Locally Advanced Mesothelioma

Hemithoracic intensity-modulated pleural radiation therapy (IMPRINT) after chemotherapy and pleurectomy-decortication is safe and has an acceptable rate of radiation pneumonitis for the treatment of patients with malignant pleural mesothelioma, a study published in the Journal of Clinical Oncology has shown.¹

For this phase 2 trial, researchers enrolled 45 patients at either Memorial Sloan Kettering Cancer Center in New York or MD Anderson Cancer Center in Houston, Texas. Patients received up to 4 cycles of chemotherapy with pemetrexed and a platinum agent. If feasible, pleurectomy-decortication was performed. Hemithoracic IMPRINT was then administered at a planned dose of 50.4 Gy in 28 fractions.

Of the 45 patients enrolled, 9 experienced disease progression before IMPRINT, 5 refused surgery or IMPRINT, 2 underwent an extrapleural pneumonectomy at the time of surgery, and 2 had chemotherapy complications.

In total, 26 patients received pemetrexed plus cisplatin, 18 had pemetrexed plus carboplatin, and 4 received a combination. Of those, 28.9% achieved a partial response, 33.3% experienced progressive disease, 1 patient died during chemotherapy, and all others had stable disease. Eight patients underwent pleurectomy-decortication or an extended version, and 13 underwent a partial pleurectomy-decortication. A total of 27 patients started hemithoracic IMPRINT.

Results showed that at a median follow-up of 21.6 months, 6 of the 27 evaluable patients experienced grade 2 radiation pneumonitis, and 2 patients experienced grade 3 radiation pneumonitis. Each recovered after the initiation of corticosteroids. No grade 4 or 5 radiation-related toxicities were observed.

Median progression-free survival was 12.4 months; median overall survival was 23.7 months. The 2-year overall survival rate was 59% and 25% among patients with resectable and unresectable tumors, respectively.

The findings suggest that incorporating hemithoracic IMPRINT with chemotherapy and pleurectomy-decortication creates a new lung-sparing treatment modality for patients with locally-advanced, malignant pleural mesothelioma.

Reference

1. Rimner A, Zauderer MG, Gomez DR, Adusumilli PS, Parhar PK, Wu AJ, et al. Phase II study of hemithoracic intensity-modulated pleural radiation Therapy (IMPRINT) as part of lung-sparing multimodality therapy in patients with malignant pleural mesothelioma [published online ahead of print June 20, 2016]. J Clin Oncol. doi: 10.1200/JCO.2016.67.2675.