Hemithoracic radiotherapy for mesothelioma: lack of benefit or lack of statistical power?

Our plain-English summary of Hemithoracic radiotherapy for mesothelioma: lack of benefit or lack of statistical power?, by A. Rimner, C.B. Simone, M.G. Zauderer, et al (The Lancet. Oncology, 2016).

The study

• Authors: A. Rimner, C.B. Simone, M.G. Zauderer, K.A. Cengel, V.W. Rusch
• Journal: The Lancet. Oncology
• Published: 2016;17(2):e43-e44
• Type of article: Letter, Comment
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This is a letter to the editor responding to the SAKK 17/04 randomised phase 2 trial by Stahel and colleagues. That trial concluded that hemithoracic radiotherapy after neoadjuvant chemotherapy and extrapleural pneumonectomy was not supported in patients with malignant pleural mesothelioma. The trial reported median locoregional relapse-free survival of 7·6 months (95% CI 4·5–10·7) without radiotherapy and 9·4 months (6·5–11·9) with radiotherapy. The letter writers argued that the trial's conclusions were not supported by its data.

They noted several problems with the trial:

• It closed early because of slow accrual.
• It did not meet its primary endpoint in part 2.
• Many patients dropped out between registration and randomisation.
• Only 23 patients received radiotherapy as prescribed, using three different fractionation regimens across 14 centres.
• One patient developed grade 4 pneumonitis and another died of pneumonitis during radiotherapy, yet the study gave no details on radiotherapy guidelines, dose to the contralateral lung, or links between dose and toxicity.
• It was unclear how boost volumes were chosen.
• There was no central review of contours or treatment plans. The only requirement was dosimetry on the first patient at each centre.

The writers concluded that the trial should be seen as inconclusive, like the MARS study of extrapleural pneumonectomy. They cited newer radiotherapy approaches under assessment and called for careful patient selection, meticulous radiotherapy technique and multidisciplinary care at high-volume centres. They declared no competing interests.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This is a letter to the editor, not a new study. The authors responded to a published trial by Stahel and colleagues (SAKK 17/04). That trial tested radiotherapy to one side of the chest (hemithoracic radiotherapy) after chemotherapy and extrapleural pneumonectomy in malignant pleural mesothelioma. The authors noted that in that trial, median locoregional relapse-free survival from surgery was 7.6 months (95% CI 4.5 to 10.7) in patients not given radiotherapy and 9.4 months (6.5 to 11.9) in the radiotherapy group. They argued that the trial could not settle the question. It closed early because of slow accrual, did not meet its primary endpoint, and lost many patients between registration and randomisation. Only 23 patients received radiotherapy as prescribed, using three different dose schedules across 14 centres. They also pointed to one case of grade 4 pneumonitis and one death from pneumonitis during radiotherapy. They said the trial gave no details on doses to the other lung, and apparently did not centrally check treatment plans for quality. The authors concluded that the trial should be interpreted as inconclusive. The letter does not discuss asbestos.

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: Letter to the editor (correspondence) commenting on a published randomised phase 2 trial; no original data
• Who was studied: No patients were studied by the letter's authors. The letter discusses the SAKK 17/04 trial by Stahel and colleagues in patients with malignant pleural mesothelioma.
• Exposure: No asbestos exposure is discussed. The treatment at issue is hemithoracic radiotherapy after neoadjuvant chemotherapy and extrapleural pneumonectomy.
• Main results:
  • The letter cites the Stahel trial's result for patients not treated with radiotherapy: median locoregional relapse-free survival from surgery was 7.6 months (95% CI 4.5 to 10.7).
  • The letter cites the Stahel trial's result for the radiotherapy group: median locoregional relapse-free survival was 9.4 months (6.5 to 11.9).
  • The authors pointed out that the Stahel trial closed early because of slow accrual and did not meet its primary endpoint in part 2.
  • The authors pointed out that the Stahel trial had substantial patient dropout between registration and randomisation.
  • The authors pointed out that in the Stahel trial only 23 patients received radiotherapy as prescribed, using three different fractionation regimens across 14 centres.
  • The authors noted that in the Stahel trial one patient developed grade 4 pneumonitis and another died of pneumonitis during radiotherapy.
  • The authors stated that the Stahel trial gave no details on radiotherapy guidelines or doses to the contralateral lung, and did not link dose measures to side effects.
  • The authors stated that, apparently, there was no central review of contours in the Stahel trial and that treatment plans were not centrally checked for quality assurance.
• The authors' conclusion: The authors concluded that the Stahel trial should be interpreted as inconclusive about the role of adjuvant hemithoracic radiotherapy. They also said that changing clinical practice on its basis would be irresponsible.

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: Mesothelioma, Neoadjuvant Therapy, Extrapleural Pneumonectomy (EPP), Pleural Mesothelioma, Pneumonitis, Multidisciplinary Team.

Related studies

• Hemithoracic radiotherapy for mesothelioma: lack of benefit or lack of statistical power? - Authors' reply — O. Riesterer, W. Weder, et al. (2016)
• Multimodal treatment for malignant pleural mesothelioma — R.C. Rintoul, T. Treasure, et al. (2015)
• Updated patterns of failure after multimodality therapy for malignant pleural mesothelioma — E.H. Baldini, W.G. Richards, et al. (2015)
• Accelerated hemithoracic radiation followed by extrapleural pneumonectomy for malignant pleural mesothelioma — M. de Perrot, R. Feld, et al. (2016)
• Trimodality strategy for treating malignant pleural mesothelioma: results of a feasibility study of induction pemetrexed plus cisplatin followed by extrapleural pneumonectomy and postoperative hemithoracic radiation (Japan Mesothelioma Interest Group 0601 Trial) — S. Hasegawa, M. Okada, et al. (2016)
• Importance of excision repair cross-complementation group 1 and ribonucleotide reductase M1 as prognostic biomarkers in malignant pleural mesothelioma treated with platinum-based induction chemotherapy followed by surgery — L. Frischknecht, M. Meerang, et al. (2015)

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