Locoregional control and toxicity after pleurectomy/decortication and intensity-modulated pleural radiation therapy in patients with malignant pleural mesothelioma

Our plain-English summary of Locoregional control and toxicity after pleurectomy/decortication and intensity-modulated pleural radiation therapy in patients with malignant pleural mesothelioma, by O. Arrieta, F. Lozano-Ruiz, M. Blake-Cerda, et al (Thoracic Cancer, 2020).

The study

• Authors: O. Arrieta, F. Lozano-Ruiz, M. Blake-Cerda, R. Catalán, L. Lara-Mejía, M.Á. Salinas, F. Maldonado-Magos, J.F. Corona-Cruz
• Journal: Thoracic Cancer
• Published: 2020;11(12):3448-3455
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Treatment of malignant pleural mesothelioma (MPM) represents a major challenge for oncologists. Multimodality treatment, which generally involves induction chemotherapy, surgery and radiotherapy have recently shown promising results. The aim of this study was to evaluate the locoregional control and toxicity of intensity modulated radiotherapy (IMRT) after pleurectomy and decortication (P/D) as part of trimodality therapy for patients with locally advanced MPM.

Methods: We prospectively analyzed data from 20 patients with MPM treated at a single tertiary-care institution. Initially every patient received induction chemotherapy with platinum-based chemotherapy. After chemotherapy, patients without progression underwent P/D, and if feasible, hemi-thoracic IMRT was administered at a planned dose of 50.4-54 Gy in 28-30 fractions and treated with 9-11 noncoplanar fields.

Results: A total of 15 of the 20 enrolled patients underwent P/D followed by IMRT to the hemi-thoracic cavity. The median total radiotherapy dose was 48.7 Gy (23.4-54 Gy). Radiation pneumonitis (RP) developed in nine patients (60%), and of these, two patients (13.3%) experienced G3 or G4 RP. The estimated locoregional-relapse-free survival at two years was 75.9%, and the main pattern of recurrence was distant (72.7%). For the entire cohort median follow-up was 22.7 months, median progression-free survival was 18.9 months and median overall survival 23.6 months.

Conclusions: Platinum-based chemotherapy followed by lung-sparing surgery (P/D) and IMRT is a feasible and safe treatment modality that yields acceptable locoregional control in patients with locally advanced MPM; however, these results should be corroborated in larger studies.

© 2020 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

In plain English

This prospective study at a cancer institute in Mexico City enrolled 20 patients with malignant pleural mesothelioma treated between October 2011 and May 2016. All patients received platinum-based chemotherapy. Those whose disease had not progressed were then to have lung-sparing surgery (pleurectomy/decortication), followed if feasible by intensity-modulated radiation to the affected side of the chest. Fifteen received all three treatments and were analyzed. Of these 15, 11 had asbestos exposure. Radiation pneumonitis, an inflammation of the lung, occurred in 9 patients (60%) and was grade 3 to 4 in 2 (13.3%). No treatment-related deaths were documented. The estimated rate of staying free of relapse in the chest at two years was 75.9%. Eleven patients had a recurrence, eight of them at distant sites. In different places the article reports median progression-free survival as 18.7 or 18.9 months, and median overall survival as 24.9 or 23.6 months. Asbestos exposure was not significantly associated with survival. The authors concluded the approach was feasible and safe with acceptable local control, but said larger studies are needed. They named the small sample and the lack of lung function tests as limitations.

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: Prospective single-institution study of trimodality treatment (induction chemotherapy, pleurectomy/decortication, hemithoracic intensity-modulated radiotherapy), with no comparison group
• Who was studied: 20 patients with confirmed malignant pleural mesothelioma treated at the Instituto Nacional de Cancerología, Mexico City, between October 2011 and May 2016. 15 completed all three treatments and were analyzed. The other 5 were excluded: 2 progressed during induction chemotherapy, 2 had extrapleural pneumonectomy and 1 progressed after P/D. Of the 15 analyzed, median age was 58, 13 were male and 14 had epithelioid histology. 11 of the 15 had asbestos exposure.
• Exposure: Treatment studied:
• platinum-based induction chemotherapy (in the 15 analyzed: cisplatin-gemcitabine in 10, cisplatin-pemetrexed in 4, cisplatin-vinorelbine in 1)
• then pleurectomy/decortication (extended, standard or partial)
• then hemithoracic IMRT planned at 50.4 to 54 Gy in 28 to 30 fractions

Asbestos exposure (yes in 11 of 15) was recorded as a baseline characteristic.

• Main results:
  • Radiation pneumonitis developed in 9 of the 15 analyzed patients (60%). It was grade 3 or 4 in 2 patients (13.3%), who needed supplementary oxygen and steroids.
  • Esophagitis occurred in 6 patients (40%), grade 3 in 2 (13.3%). Fatigue occurred in 6 patients (40%), grade 3 in 3 (20%).
  • No treatment-related deaths or grade 5 adverse events were documented.
  • Median radiotherapy dose was 48.7 Gy (range 23.4 to 54 Gy). 14 of 15 patients (93.3%) completed the planned IMRT. One stopped at 23.4 Gy because of esophageal toxicity.
  • Estimated locoregional-relapse-free survival at two years was 75.9%.
  • 11 of the 15 patients (73.3%) had a documented recurrence: 8 distant and 3 local.
  • Results section: median progression-free survival was 18.7 months (95% CI 12.6 to 24.9). One-year PFS was 72.4% and two-year PFS was 26.7%. The abstract and Table 4 instead give 18.9 months (95% CI 11.8 to 25.9).
  • Results section: median overall survival was 24.9 months (95% CI 20.9 to 26.2). One-year OS was 86.2% and two-year OS was 50.7%. The abstract and Table 4 instead give 23.6 months (95% CI 20.9 to 26.2).
  • Median OS by subgroup:
• 35.5 months after extended P/D versus 22.7 months after partial P/D (P = 0.037)
• 31.9 months with distant recurrence versus 20.9 months with locoregional recurrence (P = 0.036)
  • No baseline characteristic or chemotherapy regimen was significantly associated with PFS or OS. For asbestos exposure present versus absent, median PFS was 18.7 versus 18.9 months (P = 0.648) and median OS was 23.6 versus 22.1 months (P = 0.968).
• The authors' conclusion: The authors concluded that platinum-based chemotherapy followed by P/D and IMRT is feasible and safe, and gives acceptable locoregional control in locally advanced malignant pleural mesothelioma. They added that these results should be confirmed in larger studies. In the discussion they also wrote that the approach provides a better prognosis, although the study had no comparison group.
• Limitations the authors state:
  • Small sample size
  • Pulmonary function tests were not performed, so any harmful effect of treatment on lung function is not known

Topics

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

Medical terms in this study, explained in our Lexicon: Pleurectomy/Decortication (P/D), Pleural Mesothelioma, Chemotherapy, Trimodality Therapy, Pneumonitis, Progression-Free Survival, Median Overall Survival.

Related studies

• Disease-Related Outcomes and Toxicities of Intensity Modulated Radiation Therapy After Lung-Sparing Pleurectomy for Malignant Pleural Mesothelioma: A Systematic Review — R. Patel, E.B. Ludmir, et al. (2020)
• 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)
• Intensity modulated radiation therapy after extra-pleural pneumonectomy for malignant pleural mesothelioma is feasible without fatal pulmonary toxicity and provides good survival — S. Jhavar, J. Pruszynski, et al. (2018)
• Geometric dose prediction model for hemithoracic intensity-modulated radiation therapy in mesothelioma patients with two intact lungs — L. Kuo, E.D. Yorke, et al. (2016)
• Intensity-Modulated Radiation Therapy Improves the Target Coverage Over 3-D Planning While Meeting Lung Tolerance Doses for All Patients With Malignant Pleural Mesothelioma — S. Ulger, E. Cetin, et al. (2017)
• Current readings: improvements in intensity-modulated radiation therapy for malignant pleural mesothelioma — K.E. Rosenzweig (2013)

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