Clinical experience of volumetric modulated arc therapy for malignant pleural mesothelioma after extrapleural pneumonectomy

Our plain-English summary of Clinical experience of volumetric modulated arc therapy for malignant pleural mesothelioma after extrapleural pneumonectomy, by T. Kimura, Y. Doi, T. Nakashima, et al (Journal of Radiation Research, 2015).

The study

• Authors: T. Kimura, Y. Doi, T. Nakashima, N. Imano, T. Katsuta, S. Takahashi, M. Kenjo, S. Ozawa, Y. Murakami, Y. Nagata
• Journal: Journal of Radiation Research
• Published: 2015;56(2):315-24
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The purpose of this study was to evaluate the efficacy and safety of volumetric modulated arc therapy (VMAT) after extrapleural pneumonectomy (EPP) in patients with malignant pleural mesothelioma (MPM). A total of 15 patients who received VMAT after EPP were enrolled. All patients were males, and the median age was 67 years (Stage IB in two, II in six, and III in seven patients). The clinical target volume (CTV) included the entire preoperative ipsilateral hemithorax and involved nodal stations. The CTV was generally expanded by 10-15 mm beyond the planning target volume (PTV). The dose prescription was designed to cover 95% of the PTV with 54 Gy in 30 fractions. The median follow-up period was 11 months. Treatment-related toxicities were evaluated by Common Terminology Criteria for Adverse Events (CTCAE) ver. 4. One-year local control, disease-free survival, and overall survival rates were 55.7% [95% confidence interval (CI): 25.6-85.8%], 29.3% (95% CI: 5.3-53.3%), and 43.1% (95% CI: 17.1-69.0%), respectively. According to the histological analysis, the one-year LC rate was significantly worse in patients with non-epithelial type (biphasic and sarcomatoid types) than in patients with epithelial type [epithelial type: 83.3% (95% CI, 53.5-100%), non-epithelial type: 0% (95% CI, 0%), P = 0.0011]. Grade 3 pneumonitis after VMAT was observed in three patients (20.0%); however, no patients died of pulmonary toxicity. VMAT appears to be relatively safe for patients with MPM after EPP because of the low pulmonary dose.

© The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

In plain English

This retrospective, single-hospital study of radiotherapy for malignant pleural mesothelioma did not examine asbestos exposure. From December 2009 to January 2014, 17 patients at Hiroshima University Hospital started volumetric modulated arc therapy (VMAT), usually 54 Gy in 30 fractions, after extrapleural pneumonectomy (removal of the lung and pleura). Two stopped when their disease progressed, leaving 15 men (median age 67) for analysis. Of these, 14 had chemotherapy before surgery and one had it after surgery and VMAT. Estimated one-year rates were 43.1% for overall survival (95% CI 17.1 to 69.0%), 29.3% for progression-free survival (5.3 to 53.3%) and 55.7% for local control (25.6 to 85.8%). Local control was 83.3% (95% CI 53.5 to 100%) in 10 epithelial-type patients versus 0% in five non-epithelial-type patients (P = 0.0011). Survival differences by tumor type were not statistically significant. Three patients (20.0%) had Grade 3 pneumonitis; none died of lung toxicity. Dose limits were hard to meet for the liver in right-sided cases and the heart in left-sided cases. The authors concluded VMAT appeared feasible and relatively safe after this surgery because of the low lung dose. They noted the small numbers and short follow-up.

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 single-institution clinical case series of radiotherapy after surgery
• Who was studied: 17 patients with malignant pleural mesothelioma treated at Hiroshima University Hospital, Japan, December 2009 to January 2014. Two were excluded for progressive disease during VMAT, so 15 were analyzed. All were male, median age 67 (range 56 to 78). Histology: 10 epithelial, 2 sarcomatoid, 3 biphasic.
• Exposure: Not an asbestos exposure study. The factor studied was treatment: extrapleural pneumonectomy, adjuvant VMAT (in principle 54 Gy in 30 fractions, lowered to 50.4 Gy or 45 Gy if lung dose limits could not be met), and chemotherapy (cisplatin and pemetrexed). Per Table 2, 14 of the 15 analyzed patients had chemotherapy before surgery and VMAT, and one had it after surgery and VMAT.
• Main results:
  • Treatment sequence among the 15 analyzed patients: 14 had chemotherapy, then EPP, then VMAT. One had EPP, then VMAT, then chemotherapy (Table 2).
  • In the 15 analyzed patients, Kaplan–Meier estimates of 1-year rates, measured from the start of VMAT, were: overall survival 43.1% (95% CI 17.1 to 69.0%), progression-free survival 29.3% (95% CI 5.3 to 53.3%), and local control 55.7% (95% CI 25.6 to 85.8%).
  • 1-year local control was 83.3% (95% CI 53.5 to 100%) in the 10 epithelial-type patients versus 0% (95% CI 0%) in the 5 non-epithelial (biphasic and sarcomatoid) patients, P = 0.0011.
  • 1-year overall survival was 56.3% (95% CI 23.9 to 88.6%) for epithelial type versus 20.0% (95% CI 0 to 55.1%) for non-epithelial type, P = 0.0865. This difference was not statistically significant.
  • 1-year progression-free survival was 46.7% (95% CI 14.2 to 79.2%) for epithelial type versus 0% for non-epithelial type, P = 0.0513. This difference was not statistically significant.
  • Local, regional and distant failure occurred in 5 (33.3%), 1 (6.7%) and 7 (46.7%) of the 15 patients. Four of the 5 local failures were non-epithelial type.
  • Three of 15 patients (20.0%) developed Grade 3 pulmonary toxicity within 3 months after VMAT. No patient died of pulmonary toxicity.
  • Two patients (13.3%) had Grade 3 appetite loss.
  • Contralateral lung dose limits were met in all patients. It was difficult to keep the liver dose within limits in right-sided cases and the heart dose within limits in left-sided cases.
  • Mean lung dose, V5 and V20 did not differ significantly between patients with Grade 0 to 2 and Grade 3 pneumonitis.
• The authors' conclusion: The authors concluded that VMAT appears feasible and relatively safe for patients with MPM after EPP because of the low lung dose combined with good dose coverage of the target.
• Limitations the authors state:
  • Retrospective, single-institution design, small number of patients, and short follow-up.
  • Dose limits for the liver (right-sided cases) and heart (left-sided cases) were exceeded, so longer follow-up of liver and heart function is needed.

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, Extrapleural Pneumonectomy (EPP), Hemithorax, Disease-Free Survival, Overall Survival, confidence interval, Biphasic Mesothelioma, Sarcomatoid.

Related studies

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• Hemithoracic intensity-modulated radiotherapy using helical tomotherapy for patients after extrapleural pneumonectomy for malignant pleural mesothelioma — T. Ebara, H. Kawamura, et al. (2012)
• 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)
• Single-institution experience of intensity-modulated radiotherapy for malignant pleural mesothelioma at University of Catania — C. Spatola, C. Militello, et al. (2018)
• 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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