Volumetric Modulated Arc Therapy After Lung Sparing Surgery for Malignant Pleural Mesothelioma: A Single Institution Experience.

INTRODUCTION

We investigated the possible role of volumetric modulated arc therapy (VMAT) in the setting of adjuvant treatment of malignant pleural mesothelioma (MPM) after lung-sparing surgery with pleurectomy and decortication.

MATERIALS AND METHODS

Patients affected by MPM who had undergone pleurectomy and decortication and adjuvant radiotherapy with VMAT were included. The endpoints of the present analysis were local control, progression-free survival, and overall survival. Assessment of the variables affecting survival was performed using univariate and multivariate Cox proportional hazard models.

RESULTS

A total of 49 patients were included in the present study. Of the 49 patients, 96% had been treated with a trimodality approach. Radiotherapy was delivered to a median dose of 44 Gy in 22 fractions (range, 22-59.4 Gy). The treatment was well tolerated, with just 2 grade 3 acute toxicities, 1 grade 5, and 2 grade 4 toxicities recorded during the follow-up period. The median follow-up period was 27.4 months. The local control rate at 12, 24, and 36 months was 75.2%, 67.4%, and 56.5%, respectively. The median progression-free survival was 14.9 months (95% confidence interval [CI], 7.5-25.2). The median overall survival was 21.5 months (95% CI, 15.3-37.1). On multivariate analysis, the administration of carboplatin- instead of cisplatin-based chemotherapy (hazard ratio, 2.97; 95% CI, 1.22-7.26; P = .017) and R2 resection (hazard ratio, 1.95; 95% CI, 1.27-2.99; P = .002) showed a negative correlation with overall survival. On univariate analysis, the percentage of the heart receiving >20 Gy and >30 was associated with the occurrence of late pneumonitis (P = .018 and P = .077).

CONCLUSION

VMAT is feasible in the setting of MPM after lung-sparing surgery. The toxicity rates were reduced with this technique compared with historical data of older techniques. Local and distant failure remain a major issue to be addressed in future trials.