A Feasibility Study Evaluating Surgery for Mesothelioma After Radiation Therapy: The “SMART” Approach for Resectable Malignant Pleural Mesothelioma

Introduction:

We developed an innovative approach for malignant pleural mesothelioma (MPM) with a short accelerated course of high-dose hemithoracic intensity-modulated radiation therapy (IMRT) followed by extrapleural pneumonectomy (EPP). This phase I/II study assessed the feasibility of Surgery for Mesothelioma After Radiation Therapy (SMART).

Methods:

All resectable clinical T1-3N0M0 histologically proven, previously untreated MPMs were eligible. Patients received 25 Gy in five daily fractions during 1 week to the entire ipsilateral hemithorax with concomitant 5 Gy boost to areas at risk followed by EPP within 1 week of completing neoadjuvant IMRT. Adjuvant chemotherapy was offered to ypN2 patients on final pathologic findings. The primary end point was treatment-related mortality and secondary end points were overall survival, disease-free survival, treatment-related morbidity, and patterns of failure.

Results:

Targeted accrual of 25 patients was completed between November 2008 and October 2012. All patients completed SMART. IMRT was well tolerated with no grade 3+ toxicities. EPP was performed 6 ± 2 days after completing IMRT without any perioperative mortality. Thirteen patients developed grade 3+ surgical complications. One patient (4%) died from treatment-related toxicity (empyema) during follow-up. All but one patient had stage III or IV disease on final pathologic findings. Five of 13 ypN2 patients received adjuvant chemotherapy. After a median follow-up of 23 months (range, 6–51), the cumulative 3-year survival reached 84% in epithelial subtypes compared with 13% in biphasic subtypes (p = 0.0002).

Conclusions:

SMART is feasible in resectable MPM patients. This innovative protocol presents encouraging results and supports future studies looking at long-term outcome in patients with epithelial subtypes.