Fast neutron radiotherapy in the treatment of malignant pleural mesothelioma

Our plain-English summary of Fast neutron radiotherapy in the treatment of malignant pleural mesothelioma, by S.A. Patel, A.S. Kusano, A. Truong, et al (American Journal of Clinical Oncology, 2015).

The study

• Authors: S.A. Patel, A.S. Kusano, A. Truong, K.J. Stelzer, G.E. Laramore
• Journal: American Journal of Clinical Oncology
• Published: 2015;38(1):47-50
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Malignant pleural mesothelioma (MPM) is a fatal disease lacking standardized treatment. We describe the use of fast neutron radiation therapy in MPM patients referred to the Department of Radiation Oncology at the University of Washington Medical Center.

Materials And Methods: Retrospective chart review of MPM patients receiving neutron radiotherapy treatment from 1980 to 2012.

Results: A total of 30 MPM patients received fast neutron radiotherapy as part of their treatment regimen. Median age at diagnosis was 59.6 years (range, 46.6 to 72.3 y). Eighteen patients received fast neutron radiotherapy as a component of trimodality treatment. Median overall survival was 20.3 months (range, 5.5 to 73.3 mo) with 1 patient censored at 34.8 months and all other patients with confirmed dates of death. One patient receiving radiotherapy alone as a palliative measure died during radiation treatment. One patient was unable to tolerate radiotherapy and stopped before completing prescribed treatment. On univariate analysis, Brigham Stage at presentation was a significant predictor of survival (P<0.01). No significant differences in survival were observed when comparing patients who received trimodality treatment compared to those who did not.

Conclusions: Fast neutron radiotherapy may be utilized in the management of MPM patients. However, treatment with fast neutron radiotherapy did not significantly improvement outcome, even when used in a trimodality regimen.

In plain English

This study reviewed the charts of 30 patients with malignant pleural mesothelioma who received fast neutron radiation therapy after referral to the University of Washington radiation oncology department between January 1990 and January 2012. Most were white men with a smoking history. Asbestos exposure was reported as probable or definite in 73% of patients. Twenty-six had surgery, most often extrapleural pneumonectomy (19 patients). Thirteen received combined chemotherapy, surgery and neutron radiation (trimodality treatment). For all 30 patients, median overall survival was 20.3 months (range 5.5 to 73.3). Median survival was 22.1 months with trimodality treatment and 16.1 months without it. This difference was not statistically significant (P = 0.29), and trimodality patients more often had earlier-stage disease. Disease stage at presentation (Brigham Stage) was the only significant predictor of survival. The authors concluded that they could not show a significant survival benefit from fast neutron radiotherapy, even within trimodality treatment, and that their institution stopped using it regularly for mesothelioma. They noted the small number of patients and the retrospective design.

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 chart review (case series) at one institution
• Who was studied: 30 patients with malignant pleural mesothelioma treated with fast neutron radiotherapy at the University of Washington Medical Center, Seattle, referred January 1990 to January 2012; mostly white males with a smoking history
• Exposure: The treatment studied was fast neutron radiotherapy, at a median dose of 1800 neutron cGy (range 850 to 2040 neutron cGy), alone or combined with surgery and/or chemotherapy. Asbestos exposure history was recorded as background, but no fiber types are given.
• Main results:
  • Asbestos exposure was reported as probable or definite in 73% of the 30 patients (22 of 30 in Table 1).
  • Of 26 surgical procedures, 19 (73%) were extrapleural pneumonectomy. The remaining 7 were pleurectomy and decortication.
  • 12 patients (40%) had trimodality treatment in the order chemotherapy, then extrapleural pneumonectomy, then fast neutron radiation.
  • One further patient had trimodality treatment in the order surgery, radiation, chemotherapy.
  • Median overall survival for all patients combined was 20.3 months (range 5.5 to 73.3 months). Survival was measured from the date of initial symptoms.
  • Median survival was 22.1 months (range 7.9 to 73.3) for trimodality patients and 16.1 months (range 5.5 to 54.0) for the others. The difference was not statistically significant (P = 0.29).
  • A greater proportion of trimodality patients had earlier-stage disease (P = 0.01). 11 of 14 patients with Brigham Stage I disease received trimodality therapy.
  • On univariate analysis, Brigham Stage was the only significant variable (P = 0.02). Age, sex, histology, tobacco use, asbestos exposure and trimodality approach were not significant.
  • On multivariate analysis, Brigham Stage remained the only significant predictor of survival (hazard ratio 3.29, 95% confidence interval 1.36 to 7.96, P less than 0.01).
  • Confirmed local recurrence occurred in 15 patients and distant recurrence in 3. Another 3 had both local and distant recurrence.
  • One patient receiving radiotherapy alone as palliation died during radiation treatment. One patient could not tolerate radiotherapy and stopped early.
• The authors' conclusion: The authors concluded that they could not demonstrate significant survival benefits from fast neutron radiotherapy, even in a trimodality approach. In light of this, their institution stopped using neutron therapy on a regular basis for mesothelioma.
• Limitations the authors state:
  • Only patients who received neutron radiation were included. Patients treated with chemotherapy and/or surgery without radiation were not.
  • The small number of patients may have made survival differences hard to detect.
  • Pretreatment staging may have underestimated disease extent.
  • Detailed information on where recurrences occurred relative to the radiation fields was difficult to obtain.
  • Survival is defined differently across studies, which affects comparisons with other studies.
  • The findings are subject to the limitations of a retrospective review.

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: Pleural Mesothelioma, Median Overall Survival, Palliative Care.

Related studies

• Pleural mesothelioma treated by fast neutron therapy — P.R. Blake, M. Catterall, et al. (1985)
• Extrapleural pneumonectomy for malignant pleural mesothelioma: outcomes of treatment and prognostic factors — T.D. Yan, M. Boyer, et al. (2009)
• Trimodality Treatment of Malignant Pleural Mesothelioma: An Institutional Review — M. Kapeles, M.F. Gensheimer, et al. (2018)
• The Role of Adjuvant Radiotherapy in the Treatment of Pleural Mesothelioma — G.D. Lewis, S.M. Dalwadi, et al. (2019)
• Radiotherapy for the treatment of malignant pleural mesothelioma — M. de Perrot, L. Wu, et al. (2017)
• Extra-pleural pneumonectomy in the era of image-guided intensity-modulated radiotherapy — M. Trovo, D. Franceschini, et al. (2019)

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