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Purpose: Intensity-modulated radiation therapy (IMRT) is the state-of-the-art treatment for patients with malignant pleural mesothelioma (MPM). The goal of this work was to assess whether intensity-modulated proton therapy (IMPT) could further improve the dosimetric results allowed by IMRT., Patients and Methods: We re-planned 7 MPM cases using both photons and protons, by carrying out IMRT and IMPT plans. For both techniques, conventional dose comparisons and normal tissue complication probability (NTCP) analysis were performed. In 3 cases, additional IMPT plans were generated with different beam dimensions., Results: IMPT allowed a slight improvement in target coverage and clear advantages in dose conformity (p < 0.001) and dose homogeneity (p = 0.01). Better organ at risk (OAR) sparing was obtained with IMPT, in particular for the liver (D(mean) reduction of 9.5 Gy, p = 0.001) and ipsilateral kidney (V(20) reduction of 58%, p = 0.001), together with a very large reduction of mean dose for the contralateral lung (0.2 Gy vs 6.1 Gy, p = 0.0001). NTCP values for the liver showed a systematic superiority of IMPT with respect to IMRT for both the esophagus (average NTCP 14% vs. 30.5%) and the ipsilateral kidney (p = 0.001). Concerning plans obtained with different spot dimensions, a slight loss of target coverage was observed along with sigma increase, while maintaining OAR irradiation always under planning constraints., Conclusion: Results suggest that IMPT allows better OAR sparing with respect to IMRT, mainly for the liver, ipsilateral kidney, and contralateral lung. The use of a spot dimension larger than 3 × 3 mm (up to 9 × 9 mm) does not compromise dosimetric results and allows a shorter delivery time.

Background and Purpose: To evaluate survival, locoregional control and toxicity in a series of 56 mesothelioma patients treated from May 2005 to May 2010 with post-operative radiotherapy after extrapleural pneumonectomy (EPP) in three Italian Institutions (Brescia, Florence, and Modena)., Material and Methods: Fifty-six patients treated with adjuvant radiotherapy (RT) after EPP were analyzed. Four patients were treated with 3DCRT, 50 with IMRT and two with helical tomotherapy. Forty-five to 50 Gy in 25 fractions were given to the affected hemithorax and to ipsilateral mediastinum, with a simultaneous integrated boost to the sites of microscopically involved margins up to 60 Gy in 20/56 cases., Results: Three year locoregional control (LRC), distant metastasis free (DMF), disease free (DF), disease specific (DSS) and overall survival (OS) rates are 90%, 66%, 57%, 62%, and 60%, respectively., Conclusion: Postoperative RT with modern techniques is an effective method to obtain excellent local control and cure rates in mesothelioma patients submitted to EPP., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)