Survey of malignant pleural mesothelioma treatment in Japan: Patterns of practice and clinical outcomes in tomotherapy facilities

Our plain-English summary of Survey of malignant pleural mesothelioma treatment in Japan: Patterns of practice and clinical outcomes in tomotherapy facilities, by M. Nakanishi-Imai, T. Murai, M. Onishi, et al (Journal of Radiation Research, 2022).

The study

• Authors: M. Nakanishi-Imai, T. Murai, M. Onishi, A. Mouri, T. Komiyama, M. Omura, S. Kudo, A. Miyamoto, M. Hoshino, S. Ogawa, S. Ohashi, M. Koizumi, J. Omagari, H. Mayahara, K. Karasawa, T. Okumura, Y. Shibamoto
• Journal: Journal of Radiation Research
• Published: 2022;63(2):281-289
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

We conducted a nationwide survey of tomotherapy for malignant pleural mesothelioma (MPM) in Japan. Fifty-six facilities were surveyed and data on 31 patients treated curatively between 2008 and 2017 were collected from 14 facilities. Twenty patients received hemithorax irradiation after extrapleural pneumonectomy (EPP) (first group). Five patients received irradiation without EPP (second group), while six received salvage radiotherapy for local recurrence (salvage group). Among the seven patients not undergoing EPP, five (four in the second group and one in the salvage group) were treated with lung sparing pleural irradiation (LSPI) and two with irradiation to visible tumors. Two-year overall survival (OS) rates in the first and second groups were 33% and 60%, respectively (median, 13 vs 30 months, P = 0.82). In the first and second groups, 2-year local control (LC) rates were 53 and 67%, respectively (P = 0.54) and 2-year progression-free survival (PFS) rates were 16% and 60%, respectively (P = 0.07). Distant metastases occurred in 15 patients in the first group and three in the second group. In the salvage group, the median OS was 18 months. Recurrence was observed in the irradiated volume in four patients. The contralateral lung dose was higher in LSPI than in hemithorax irradiation plans (mean, 11.0 ± 2.2 vs 6.1 ± 3.1 Gy, P = 0.002). Grade 3 or 5 lung toxicity was observed in two patients receiving EPP and hemithorax irradiation, but not in those undergoing LSPI. In conclusion, outcomes of EPP and hemithorax irradiation were not satisfactory, whereas LSPI appeared promising and encouraging.

© The Author(s) 2022. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.

In plain English

This was a nationwide survey of Japanese hospitals with a tomotherapy radiation machine. It covered patients with malignant pleural mesothelioma treated with curative intent between 2008 and 2017, and data on 31 patients from 14 facilities were analyzed. Twenty had extrapleural pneumonectomy (EPP) followed by radiation to the whole side of the chest (first group). Five had radiation without surgery (second group), and six had radiation for a local recurrence (salvage group). Two-year overall survival was 33% in the first group and 60% in the second (P = 0.82). Two-year progression-free survival was 16% and 60% (P = 0.07). Distant spread occurred in 15 first-group and three second-group patients. In the first and second groups, survival showed no statistically significant difference by history of asbestos exposure. Lung-sparing pleural irradiation, given to five patients, gave a higher dose to the opposite lung than whole-chest-side plans, but none of those five had grade 3 or worse lung toxicity. One grade 3 and one grade 5 lung toxicity occurred in patients who had EPP. The authors concluded that results of EPP plus hemithorax radiation were not satisfactory, while lung-sparing irradiation appeared promising and encouraging.

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: Nationwide questionnaire survey (retrospective, multicenter) of patients treated with tomotherapy
• Who was studied: 31 patients with malignant pleural mesothelioma (MPM) treated with curative intent at 14 Japanese facilities (2 academic, 12 community hospitals) between 2008 and 2017: 20 in the first group (EPP plus hemithorax radiotherapy), 5 in the second group (radiotherapy without surgery), 6 in the salvage group (radiotherapy for local recurrence)
• Exposure: The study's subject was treatment, not asbestos. Patients received tomotherapy radiation of 40 Gy or more, as whole hemithorax irradiation (WHI), lung sparing pleural irradiation (LSPI) or irradiation of visible tumors only, with or without extrapleural pneumonectomy, chemotherapy and hyperthermia. History of asbestos exposure was collected, but no fiber types are named.
• Main results:
  • Two-year overall survival was 33% in the first group (EPP plus hemithorax radiation) and 60% in the second group (no surgery). Median survival was 13 vs 30 months, P = 0.82.
  • Two-year local control was 53% in the first group and 67% in the second group (P = 0.54).
  • Two-year progression-free survival was 16% in the first group and 60% in the second group (P = 0.07).
  • Distant metastases were the most frequent recurrence pattern in the first group (15 cases). Distant metastases occurred in three cases in the second group.
  • In the salvage group, median overall survival after irradiation was 18 months (range 9 to 78 months), and local recurrence was observed in four cases.
  • Asbestos exposure history in the first group was 11 exposed, 5 not exposed and 4 unknown (Table 1).
  • In the first and second groups (not the salvage group), overall survival showed no statistically significant difference by asbestos exposure (yes vs no vs unknown) or by several other factors (P of 0.26 or greater).
  • The mean dose to the opposite lung was higher with LSPI than with hemithorax irradiation plans: 11.0 plus or minus 2.2 Gy vs 6.1 plus or minus 3.1 Gy, P = 0.02 in the article body.
  • Grade 3 and grade 5 lung toxicity occurred in one patient each, both of whom had undergone EPP. Grade 3 pneumonitis was not observed in the LSPI patients.
• The authors' conclusion: The authors concluded that outcomes of EPP and hemithorax irradiation (the tri-modality strategy) were not satisfactory, while LSPI appeared promising and encouraging, and that further nationwide surveys are warranted.
• Limitations the authors state:
  • The small sample size probably explains why some differences were not statistically significant.
  • A higher level of evidence is needed from further surveys.

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, Hemithorax, Extrapleural Pneumonectomy (EPP), Overall Survival, Progression-Free Survival.

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• Mesothelioma at era of helical tomotherapy: results of two institutions in combining chemotherapy, surgery and radiotherapy — A. Sylvestre, M.A. Mahé, et al. (2011)
• Malignant pleural mesothelioma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up — R.A. Stahel, W. Weder, et al. (2010)
• Clinical experience of volumetric modulated arc therapy for malignant pleural mesothelioma after extrapleural pneumonectomy — T. Kimura, Y. Doi, et al. (2015)
• 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)
• Tomotherapy after pleurectomy or decortication or biopsy for malignant pleural mesothelioma — M. Trovo, E. Minatel (2013)

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