Hemithoracic intensity-modulated radiotherapy using helical tomotherapy for patients after extrapleural pneumonectomy for malignant pleural mesothelioma

Our plain-English summary of Hemithoracic intensity-modulated radiotherapy using helical tomotherapy for patients after extrapleural pneumonectomy for malignant pleural mesothelioma, by T. Ebara, H. Kawamura, T. Kaminuma, et al (Journal of Radiation Research, 2012).

The study

• Authors: T. Ebara, H. Kawamura, T. Kaminuma, M. Okamoto, D. Yoshida, Y. Okubo, T. Takahashi, K. Kobayashi, H. Sakaguchi, Y. Ando, T. Nakano
• Journal: Journal of Radiation Research
• Published: 2012;53(2):288-94
• Type of article: Case report
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Postoperative hemithoracic irradiation is regarded as an important part of the curative treatment for resectable malignant pleural mesothelioma (MPM). Because the clinical target volume in postoperative MPM is irregular and surrounded by dose-limiting critical structures, intensity-modulated radiation therapy (IMRT) is thought to be suitable. However, postoperative hemithoracic IMRT remains experimental due to a high incidence of fatal pneumonitis. Therefore, a Phase I dose escalation study for hemithoracic IMRT using helical tomotherapy was planned, and the results of the first three patients are herein reported because this technique may provide benefits to such patients. For 3 patients with postoperative MPM, who were treated by extrapleural pneumonectomy (EPP), a radiation dose of 45.0 Gy in 25 fractions was given to cover 95% of the PTV. The lung V5s of the three patients were 14.3%, 10.0%, and 31.3%, respectively. The V5s of the present plans was smaller than that of the recent IMRT planning studies. The lung V20s of these patients were 2.4%, 2.2%, and 4.3%, respectively. Their MLDs were 4.3 Gy, 3.4 Gy, and 5.8 Gy, respectively. The follow-up periods of the patients were 26, 14 and 9 months from initiation of IMRT, respectively. All patients were alive, although local and contralateral recurrences had developed in 1 patient. Only 1 patient had Grade 2 acute esophagitis and nausea. There was no treatment-related pneumonitis. Hemithoracic IMRT using helical tomotherapy may play a crucial role in adjuvant treatment for MPM after EPP.

In plain English

This article reported the first three patients treated in a Phase I dose-escalation study of radiation to one side of the chest (hemithoracic intensity-modulated radiotherapy, delivered with helical tomotherapy). All three had malignant pleural mesothelioma and had undergone extrapleural pneumonectomy, surgery that removes the lung and the lining of the chest. Enrolled from February 2009 to July 2010, all were men with left-sided epithelioid tumors, and all received 45 Gy in 25 fractions. Radiation-dose limits for nearby normal organs were met in all three. The share of remaining lung receiving at least 5 Gy was 14.3%, 10.0% and 31.3%. This was lower than in two published planning studies, but doses to the spinal cord and esophagus were higher. At follow-up of 26, 14 and 9 months, all three were alive. One had cancer return locally and spread in the opposite lung. One had Grade 2 esophagitis and nausea, and none had treatment-related pneumonitis. The authors concluded the technique may play a crucial role after this surgery. They noted that only 3 patients were studied, follow-up was short, and all tumors were left-sided.

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: Report of the first three patients treated in a Phase I dose-escalation study (a small early-stage treatment study with no comparison group)
• Who was studied: 3 men (ages 67, 56 and 67) with left-sided epithelioid malignant pleural mesothelioma, enrolled February 2009 to July 2010. All had extrapleural pneumonectomy. One (case 1) was treated for a recurrence after that surgery; the other two received radiotherapy as additional treatment after chemotherapy and surgery. The authors are from institutions in Japan.
• Exposure: The study examined a radiation treatment, not asbestos exposure: hemithoracic intensity-modulated radiotherapy using helical tomotherapy, 45.0 Gy in 25 fractions (the first dose level). Planned higher levels were 50.4 Gy in 28 fractions and 54.0 Gy in 30 fractions. All patients had earlier received cisplatin-based chemotherapy.
• Main results:
  • Dose limits for normal tissues were met in all three patients.
  • For each of the three patients in turn: the percentage of lung receiving at least 5 Gy (V5) was 14.3%, 10.0% and 31.3%; at least 20 Gy (V20) was 2.4%, 2.2% and 4.3%; and mean lung dose was 4.3 Gy, 3.4 Gy and 5.8 Gy.
  • Compared with two published treatment-planning studies by other groups (after adjusting for differences in prescribed dose), lung V5 in these patients was smaller, lung V20 was larger, and mean lung dose was similar.
  • In the same comparison, doses to the spinal cord and esophagus were larger in these patients.
  • Follow-up was 26, 14 and 9 months, and all three patients were alive at last follow-up. One patient (case 2) developed local recurrence and pleural dissemination in the opposite lung.
  • Only one patient (case 1) had Grade 2 acute esophagitis and nausea. No patient had treatment-related pneumonitis.
• The authors' conclusion: The authors concluded that hemithoracic IMRT using helical tomotherapy may play a crucial role in additional treatment for malignant pleural mesothelioma after extrapleural pneumonectomy, and that it appeared to cause only mild side effects.
• Limitations the authors state:
  • Only 3 patients were evaluated, with short follow-up. The authors stated that more patients and longer follow-up are needed.
  • All patients had left-sided disease, so radiation-induced liver damage could not be properly evaluated.
  • Comparing doses with other studies needs careful interpretation, because dose prescriptions and patient characteristics differed.

Topics

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

Medical terms in this study, explained in our Lexicon: Intensity-Modulated Radiation Therapy (IMRT), Extrapleural Pneumonectomy (EPP), Pleural Mesothelioma, Pneumonitis.

Related studies

• Patterns of failure, toxicity, and survival after extrapleural pneumonectomy and hemithoracic intensity-modulated radiation therapy for malignant pleural mesothelioma — D.R. Gomez, D.S. Hong, et al. (2013)
• High-dose-rate surface brachytherapy to boost elongated, curvilinear incisional scars after extrapleural pneumonectomy for malignant pleural mesothelioma treated with adjuvant intensity-modulated radiation therapy — L.A. Doyle, T.N. Showalter, et al. (2010)
• Hemithoracic radiation therapy after extrapleural pneumonectomy for malignant pleural mesothelioma: Toxicity and outcomes at an Australian institution — A. Bece, M.M. Tin, et al. (2015)
• Clinical experience of volumetric modulated arc therapy for malignant pleural mesothelioma after extrapleural pneumonectomy — T. Kimura, Y. Doi, et al. (2015)
• Intensity-modulated radiotherapy after extrapleural pneumonectomy in the combined-modality treatment of malignant pleural mesothelioma — A. Chi, Z. Liao, et al. (2011)
• Extra-pleural pneumonectomy in the era of image-guided intensity-modulated radiotherapy — M. Trovo, D. Franceschini, et al. (2019)

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