Author of

• 20188

  +

  P3.09 - Mesothelioma (ID 725)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Mesothelioma
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 24129

    +

    P3.09-001 - The Dosimetric Advantages of Intensity Modulated Proton Therapy (IMPT) for Mesothelioma after Pleurectomy/Decortication  (ID 8879)

    09:30 - 09:30  |  Author(s): S.E. Beamer
    • Abstract

    Background:
    Radiotherapy (RT) after surgery for locoregionally advanced mesothelioma is particularly challenging. Recent surgical advances with pleurectomy and decortication techniques are clinically promising, however, applying comprehensive ipsilateral pleural irradiation is technically difficult with two RT-sensitive, intact lungs. With state-of-the-art IMPT, we have successfully treated a 77-year-old woman who has now been disease-free and alive for 7 months after RT (and 18 months since diagnosis), with minimal therapy-related toxicities so far.
    
    Method:
    A woman was diagnosed with locally advanced mesothelioma of the right hemithorax, epithelioid type. She underwent appropriate metastatic workup which was negative. She received 4 cycles of carboplatin and pemetrexed, and underwent thoracotomy with parietal and visceral pleurectomies, decortication, and mediastinal nodal dissection. She was found to have ypT3, N0 disease postoperatively, and elected to undergo proton therapy. A 4D-CT simulation scan was performed, and negligible respiratory motions were found.
    
    Result:
    A 3-field, active beam scanning, multi-field optimization IMPT plan was made and passed quality assurance. She received 50.4 Gy in 28 fractions, and completed IMPT without any treatment interruption; the acute toxicities included mild pain, cough, and dyspnea which were all grade 1. She also developed subacute, RT-related grade 1 dermatitis. She has not had clinically significant RT-induced pneumonitis. In preparation for her proton therapy-based treatment, multiple dosimetric iterations and comparisons were made, for the best intensity modulated radiotherapy (photon-based, IMRT) vs. IMPT plans (see Figure). With IMPT, the contralateral (left) lung, heart, and also esophagus received significant amount of RT reduction in an otherwise historically morbid adjuvant treatment which were only reserved for the medically fittest. Figure 1
    
    
    
    Conclusion:
    Although promising, the clinical dosimetric levels of evidence are limited to this case report only. The paradigm of neoadjuvant platinum-based doublet therapy, pleurectomy/decortication, and adjuvant proton RT should be further explored and evaluated in the prospective settings in the future.