Preliminary results of entire pleural intensity-modulated radiotherapy in a neoadjuvant setting for resectable malignant mesothelioma

Our plain-English summary of Preliminary results of entire pleural intensity-modulated radiotherapy in a neoadjuvant setting for resectable malignant mesothelioma, by J.H. Hong, H.C. Lee, K.H. Choi, et al (Radiation Oncology Journal, 2019).

The study

• Authors: J.H. Hong, H.C. Lee, K.H. Choi, S.W. Moon, K.S. Kim, S.H. Hong, J.Y. Hong, Y.S. Kim
• Journal: Radiation Oncology Journal
• Published: 2019;37(2):101-109
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Purpose: The purpose of this study is to evaluate the safety and efficacy of the multimodality treatment with neoadjuvant intensitymodulated radiotherapy (IMRT) for resectable clinical T1-3N0-1M0 malignant pleural mesothelioma (MPM).

Materials And Methods: A total of eleven patients who received neoadjuvant chemotherapy and radiotherapy between March 2016 and June 2018 were reviewed. Patients received 25 Gy in 5 fractions to entire ipsilateral hemithorax with helical tomotherapy.

Results: All of patients were men with a median age of 56 years. Epithelioid subtype was found in 10 patients. All patients received neoadjuvant chemotherapy with pemetrexed-cisplatin regimen. Ten patients (90.9%) completed 25 Gy/5 fractions and one (9.0%) completed 20 Gy/4 fractions of radiotherapy. IMRT was well tolerated with only one acute grade 3 radiation pneumonitis. Surgery was performed 1 week (median, 8 days; range, 1 to 15 days) after completing IMRT. Extrapleural pneumonectomy was performed in 4 patients (36.3%), extended pleurectomy/decortication in 2 (18.2%) and pleurectomy/decortications in 5 (63.6%). There was no grade 3+ surgical complication except two deaths after EPP in 1 month. Based on operative findings and pathologic staging, adjuvant chemotherapy was delivered in 7 patients (63.6%), and 2 (18.2%) were decided to add adjuvant radiotherapy. After a median follow-up of 14.6 months (range, 2.8 to 30 months), there were 3 local recurrence (33.3%) and 1 distant metastasis (11.1%).

Conclusion: Neoadjuvant entire pleural IMRT can be delivered with a favorable radiation complication. An optimal strategy has to be made in resectable MPM patients who would benefit from neoadjuvant radiation and surgery. Further studies are needed to look at long-term outcomes.

In plain English

This article reported early results from a hospital in Seoul, Korea, for SMART, a treatment plan for malignant pleural mesothelioma judged removable by surgery. The authors reviewed 11 patients, all men (median age 56), treated from March 2016 to June 2018. Each received chemotherapy, mainly pemetrexed and cisplatin. Next came radiation to the whole affected side of the chest, planned as 25 Gy in 5 fractions (one patient completed 20 Gy in 4), then surgery a median of 8 days later. The article did not report the patients' asbestos exposure. Four patients had radiation pneumonitis (lung inflammation), one at grade 3. Six patients (54.5%) had complications of grade 3 or higher. Two died within 90 days after extrapleural pneumonectomy, from a sudden heart-rhythm problem and aspiration pneumonia. Over a median follow-up of 14.6 months, three patients had cancer return on the same side of the chest, and one of these later developed distant spread. Median overall survival was 14.6 months. The authors concluded the approach can be feasible with favorable radiation complications, noting the small number of patients 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 review of patients treated under a single-institution protocol (Surgery for Mesothelioma After Radiation Therapy, SMART), evaluating short-term outcomes and safety
• Who was studied: 11 patients with histologically confirmed malignant pleural mesothelioma, clinical stage T1-3N0-1M0, treated at Seoul St. Mary's Hospital, Korea, between March 2016 and June 2018. Of 15 patients given radiotherapy, 4 were excluded because the treatment was not preoperative. All were male, median age 56 (range 36 to 69). Ten had epithelioid and one biphasic histology.
• Exposure: This was a treatment study, not a study of asbestos exposure, and patients' asbestos exposure was not reported. Treatment was at least two cycles of neoadjuvant chemotherapy (pemetrexed 500 mg/m2 with cisplatin 75 mg/m2; one patient also received carboplatin and gemcitabine). Next came intensity-modulated radiotherapy (helical tomotherapy) to the entire ipsilateral hemithorax, prescribed as 25 Gy in 5 fractions over 1 week. Ten patients completed that course and one completed 20 Gy in 4 fractions. Surgery followed: extrapleural pneumonectomy (EPP), extended pleurectomy/decortication (EP/D) or pleurectomy/decortication (P/D).
• Main results:
  • Ten patients (90.9%) completed 25 Gy in 5 fractions of radiotherapy and one (9.0%) completed 20 Gy in 4 fractions.
  • The authors reported that all 11 patients completed chemotherapy, radiotherapy and surgery, and none dropped out.
  • After two cycles of neoadjuvant cisplatin-pemetrexed, 3 patients (27.3%) showed partial remission and 8 (72.7%) stable disease.
  • Surgery took place a median of 8 days (range 1 to 15) after radiotherapy ended. EPP was done in 4 patients (36.4%), EP/D in 2 (18.2%) and P/D in 5 (45.5%).
  • Four patients had radiation pneumonitis. One, with grade 3 pneumonitis, was hospitalized and treated with steroids.
  • Six of 11 patients (54.5%) had complications of grade 3 or higher. Five patients had grade 3 or higher surgical complications: three grade 3 and two grade 5 (fatal).
  • Two patients (18.2%) died within 90 days after EPP: one at 31 days from sudden arrhythmia, one at 16 days from aspiration pneumonia.
  • Over a median follow-up of 14.6 months, 3 patients had recurrence in the ipsilateral pleura, at 5.5, 8.1 and 10.6 months after surgery. The article gives this as 33.3% without stating the denominator; 3 of all 11 patients would be 27.3%.
  • One of those 3 patients later developed distant spread (contralateral lung nodules and retroperitoneal lymph nodes), and no other patient had distant metastasis. The article gives this elsewhere as 11.1%, again without stating the denominator.
  • Mean overall survival was 23.0 months and median overall survival 14.6 months. Three patients (27.3%) died, all without evidence of recurrence.
• The authors' conclusion: The authors concluded that a short, high-dose course of hemithoracic IMRT before surgery can be feasible with favorable radiation complications. They added that patients must be selected carefully and that longer-term studies are needed.
• Limitations the authors state:
  • Short follow-up period and small number of patients.
  • Patients had different surgical methods and different adjuvant chemotherapy, which could affect toxicity and survival.

Topics

Medical terms in this study, explained in our Lexicon: Intensity-Modulated Radiation Therapy (IMRT), Mesothelioma, Pleural Mesothelioma, Neoadjuvant Therapy, Hemithorax, Epithelioid, Pemetrexed (Alimta), Cisplatin.

Related studies

• Long-term results in malignant pleural mesothelioma treated with neoadjuvant chemotherapy, extrapleural pneumonectomy and intensity-modulated radiotherapy — C. Thieke, N.H. Nicolay, et al. (2015)
• Impact of Neoadjuvant and Adjuvant Pleural Intensity-Modulated Radiotherapy in Multimodality Treatment for Malignant Pleural Mesothelioma — B. Mosleh, S. Schwarz, et al. (2025)
• Intensity-modulated radiotherapy after extrapleural pneumonectomy in the combined-modality treatment of malignant pleural mesothelioma — A. Chi, Z. Liao, et al. (2011)
• Adjuvant intensity-modulated proton therapy in malignant pleural mesothelioma. A comparison with intensity-modulated radiotherapy and a spot size variation assessment — S. Lorentini, M. Amichetti, et al. (2012)
• Intensity-modulated radiotherapy for relapsed malignant pleural mesothelioma — C. Spatola, C. Militello, et al. (2016)
• Intensity-modulated radiotherapy and volumetric-modulated arc therapy for malignant pleural mesothelioma after extrapleural pleuropneumonectomy — J. Krayenbuehl, O. Riesterer, et al. (2013)

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