High-dose palliative radiotherapy for malignant pleural mesothelioma

Our plain-English summary of High-dose palliative radiotherapy for malignant pleural mesothelioma, by F. Foroudi, J.G. Smith, F. Putt, et al (Journal of Medical Imaging and Radiation Oncology, 2017).

The study

• Authors: F. Foroudi, J.G. Smith, F. Putt, M. Wada
• Journal: Journal of Medical Imaging and Radiation Oncology
• Published: 2017;61(6):797-803
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: High-dose radiotherapy to the hemithorax for patients with malignant pleural mesothelioma is a controversial treatment. Between 2003 and 2013 our institution had a policy of giving hemithoracic radiotherapy to at least 45 Gy. This retrospective study reports survival, progression and toxicity associated with this policy.

Methods: Seventy-one patients with pleural mesothelioma were irradiated with doses of 45-60 Gy. Conformal radiotherapy (3D-CRT) to the lower hemithorax was used for 17 and intensity-modulated radiotherapy (IMRT) to the whole hemithorax for 54 patients. All patients have been followed up for at least 2 years from commencement of radiotherapy.

Results: Sixty-four patients (90%) completed planned radiotherapy and seven stopped early, usually due to progressive disease. Median overall survival was 9.5 months (95% CI: 7.7-12.4) and median progression-free survival was 4.9 months (95% CI: 4.4-5.8). Eighty-seven per cent of patients progressed or died within 2 years: 25% in-field, 49% outside the RT field and 13% died without progression. Severe toxicity (grade 3-5) was observed in 53% of 3D-CRT and 78% of IMRT patients, most commonly pulmonary fibrosis 27%, radiation dermatitis 18%, dyspnoea 11%, GGT increased 11%, pneumonitis 10%, pleuritic pain 8% and fatigue 8%. There were two, possibly three, treatment-related deaths.

Conclusion: High-dose radiotherapy to the hemithorax caused significant toxicity to most patients with no improvement in survival. Lower doses of radiotherapy to limited volumes may be useful for palliative purposes.

© 2017 The Royal Australian and New Zealand College of Radiologists.

In plain English

This retrospective study reviewed 71 patients with malignant pleural mesothelioma who began high-dose chest radiotherapy in Melbourne, Australia, between 2003 and 2013. It examined treatment results, not asbestos exposure. Patients were planned to receive 45 to 60 Gy: 17 by conformal radiotherapy (3D-CRT) and 54 by intensity-modulated radiotherapy (IMRT) to the whole side of the chest, and seven did not complete treatment. From the start of radiotherapy, median overall survival was 9.5 months (95% CI 7.7 to 12.4) and median progression-free survival was 4.9 months (95% CI 4.4 to 5.8). By 2 years, an estimated 25% had first progressed in the radiation field (including simultaneous and unspecified-site progressions), 49% outside it, and 13% had died without recorded progression. Severe side effects (grade 3 to 5) affected 9 of 17 3D-CRT patients (53%, CI 28 to 77%) and 42 of 54 IMRT patients (78%, CI 64 to 88%), most often pulmonary fibrosis (27% of all patients). Two, possibly three, deaths were treatment-related. The authors concluded the toxicities outweighed the treatment's potential benefits. Symptom relief was not formally assessed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: retrospective review of patients treated at a single institution
• Who was studied: 71 patients with histologically confirmed pleural mesothelioma treated at Austin Health, Melbourne, Australia, with planned radiotherapy doses of at least 45 Gy. Of 74 eligible patients, 3 with prior extrapleural pneumonectomy were excluded. Treatment started between 31 July 2003 and 15 July 2013.
• Exposure: Asbestos exposure was not studied. The study examined high-dose radiotherapy, with planned doses of 45 to 60 Gy over 6 weeks. Seventeen patients had 3D conformal radiotherapy (3D-CRT) to the lower hemithorax and 54 had intensity-modulated radiotherapy (IMRT) to the whole hemithorax.
• Main results:
  • Seven patients (one 3D-CRT, six IMRT) did not complete treatment: six because of progressive disease, and one chose to miss the last fraction.
  • Median overall survival, measured from the start of radiotherapy, was 9.5 months (95% CI 7.7 to 12.4) for all 71 patients.
  • Median progression-free survival, measured from the start of radiotherapy, was 4.9 months (95% CI 4.4 to 5.8) for all patients.
  • At 2 years, the estimated cumulative incidences were 25% for first progression in the radiotherapy field (including simultaneous and non-specific progressions), 49% for first progression outside the field, and 13% for death without recorded progression.
  • Survival of the 3D-CRT patients was similar to that of the IMRT patients.
  • Patients with good pre-treatment performance status (ECOG 0 to 1) had a median survival of 11.1 months, compared with 4.9 months for those with ECOG 2 to 3 (P = 0.021).
  • Severe toxicity (grade 3 to 5) occurred in 9 of 17 3D-CRT patients (53%, CI 28 to 77%) and in 42 of 54 IMRT patients (78%, CI 64 to 88%).
  • The most common severe toxicity was pulmonary fibrosis, in 27% of all patients.
  • There were two, possibly three, treatment-related deaths: two from radiation pneumonitis, and one patient with myelitis possibly related to radiotherapy.
  • Planned doses exceeded pre-specified dose limits for the heart in 72% of cases. The limits were also exceeded for the liver in 13%, the oesophagus in 6%, the thecal sac in 6%, the opposite lung in 13% and the opposite kidney in 1%.
• The authors' conclusion: The authors concluded that the toxicities of this high-dose hemithoracic radiotherapy outweighed its potential benefits.
• Limitations the authors state:
  • Patients were not formally assessed for palliative (symptom-relief) response.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Palliative Care, Pleural Mesothelioma, Hemithorax, Intensity-Modulated Radiation Therapy (IMRT), Median Overall Survival, Progression-Free Survival, Pulmonary Fibrosis, Pneumonitis.

Related studies

• Re-evaluating the role of palliative radiotherapy in malignant pleural mesothelioma — P. Jenkins, R. Milliner, et al. (2011)
• Tomotherapy after pleurectomy/decortication or biopsy for malignant pleural mesothelioma allows the delivery of high dose of radiation in patients with intact lung — E. Minatel, M. Trovo, et al. (2012)
• High dose irradiation after pleurectomy/decortication or biopsy for pleural mesothelioma treatment — E. Parisi, A. Romeo, et al. (2017)
• Establishing locoregional control of malignant pleural mesothelioma using high-dose radiotherapy and (18) F-FDG PET/CT scan correlation — M. Feigen, S.T. Lee, et al. (2011)
• Intensity-modulated radiotherapy for relapsed malignant pleural mesothelioma — C. Spatola, C. Militello, et al. (2016)
• Extra-pleural pneumonectomy in the era of image-guided intensity-modulated radiotherapy — M. Trovo, D. Franceschini, et al. (2019)

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