The Effects of Preserving the Diaphragm on Early and Late Outcome of Lung-Sparing Radical Surgery for Malignant Pleural Mesothelioma

Our plain-English summary of The Effects of Preserving the Diaphragm on Early and Late Outcome of Lung-Sparing Radical Surgery for Malignant Pleural Mesothelioma, by M. Lee, L. Ventura, R. Baranowski, et al (Journal of Clinical Medicine, 2022).

The study

• Authors: M. Lee, L. Ventura, R. Baranowski, J. Hargrave, D. Waller
• Journal: Journal of Clinical Medicine
• Published: 2022;11(22)
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The accepted aim of radical surgery for malignant pleural mesothelioma (MPM) is the achievement of macroscopic complete resection (MCR) whilst reducing perioperative morbidity by preserving normal tissue. Whilst preservation of the lung by pleurectomy/decortication (PD) has become widely utilised, there remains debate regarding the management of the diaphragm. Muscle-sparing complete excision of the diaphragmatic pleura is technically challenging; thus, surgeons may proceed to extended PD with phrenectomy and possible increased morbidity or to preserve the diaphragmatic pleura at the expense of MCR with potential survival deficit. We aimed to evaluate the effects of an intentional change in protocol to diaphragm-sparing PD whilst maintaining MCR as the treatment of choice for MPM.

Methods: In a series of 136 patients (111M:25F, median age 68(63-73) years) undergoing radical surgery for MPM, we identified 28 patients (22M:6F, median age 67(60-71) years) in whom MCR was achieved without phrenectomy (PD group). We compared their perioperative outcomes and survival with a historical control group of 18 patients (18M:0F, median age 69(57-78) years) in whom MCR had been achieved with phrenectomy (EPD group) but in whom there was no histological evidence of diaphragm muscle invasion and who, in retrospect, could have undergone muscle-sparing MCR if this procedure had been attempted.

Results: There was no significant intergroup difference in demographics or tumour cell type; the majority of both groups were found to be epithelial (PD 85.7%, EPD 77.8%). The EPD group was found to be more locally advanced (T3 55.56%) than the PD group (T1 46.43%) (p = 0.03). All the following parameters were significantly reduced after PD compared to EPD: operative time (188 vs. 220 min, p = 0.007); duration of air leak (5 vs. 10 days, p = 0.001), duration of inotrope (p = 0.009) and post-operative hospital stay (8 vs. 13 days, p = 0.034). There were no significant differences (p = 0.123) in overall survival (OS) between the two groups, but the median survival in the PD group had not been reached at a median follow up of 33.9 (24.2-46) months.

Conclusions: A surgical strategy of attempting to spare the diaphragm whilst still achieving MCR wherever possible is justified by improved perioperative outcomes without compromising OS.

In plain English

This study from St Bartholomew's Hospital in London looked back at patients who had surgery for malignant pleural mesothelioma (cancer of the lining around the lung). It did not study asbestos exposure. Of 136 patients operated on between December 2017 and August 2022, it compared 28 whose visible tumour was all removed while the diaphragm muscle was kept (PD group) with 18 earlier patients whose diaphragm was removed even though tissue examination showed no invasion of the diaphragm muscle (EPD group). The PD group had shorter operations (median 188 vs 220 minutes), a shorter air leak from the lung (median 5.5 vs 10 days), shorter use of blood-pressure drugs, and shorter hospital stays (median 8 vs 13 days). Overall survival was not significantly different (p = 0.123). Median survival was 25.66 months in the EPD group and had not been reached in the PD group. The authors concluded that sparing the diaphragm wherever possible was justified, provided all visible tumour was still removed, even if part of the muscle had to be removed. They noted that the small number of patients limited the analysis.

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 comparison of two surgical approaches using hospital records, with a historical control group. It was registered as a clinical audit.
• Who was studied: Out of 136 patients who had radical surgery for malignant pleural mesothelioma at St Bartholomew's Hospital, London (December 2017 to August 2022), two groups were compared: 28 patients (22 men, 6 women, median age 67) in the PD group and 18 patients (all men, median age 69) in the historical EPD group.
• Exposure: Asbestos exposure was not studied or reported. The comparison was between two operations: pleurectomy/decortication that kept the diaphragm (PD), and extended pleurectomy/decortication with removal of the diaphragm (phrenectomy, EPD). In both groups all visible tumour was removed, and in the EPD group there was no histological evidence of diaphragm muscle invasion.
• Main results:
  • Operations were shorter in the PD group: median 188 minutes (range 112 to 271) versus 220 minutes (range 173 to 385) in the EPD group; p = 0.007.
  • Hospital stay was shorter in the PD group: median 8 days (range 4 to 23) versus 13 days (range 5 to 22) in the EPD group; p = 0.034.
  • Air leak from the lung after surgery lasted for a shorter time in the PD group. Table 3 gives a median of 5.5 days in the PD group versus 10 days in the EPD group; p = 0.001.
  • The PD group needed inotropes (drugs to support blood pressure) for a shorter time: mean 0.62 days in the PD group versus 1.39 days in the EPD group; p = 0.009.
  • Pneumonia, atrial fibrillation and chyle leak occurred at similar rates in both groups.
  • Three of the 18 EPD patients (16.67%) developed type 1 respiratory failure, compared with none of the 28 PD patients. Table 3 gives p = 0.054, which is not statistically significant.
  • At a median follow-up of 33.9 months, overall survival did not differ significantly between the groups (p = 0.123). Median survival in the PD group had not been reached.
  • Survival at 36 months was 57.60% in the PD group (8 deaths among 28 patients), compared with 26.85% in the EPD group (10 deaths among 18 patients, median survival 25.66 months).
  • The EPD group had more locally advanced tumours: T3 in 55.56% of the EPD group, while T1 was most common in the PD group (46.43%); p = 0.03.
  • Diaphragm-sparing surgery was more often successful on the right side: 21 of the 28 PD patients (75.00%) had right-sided operations, while 13 of the 18 EPD patients (72.22%) had left-sided operations; p = 0.004.
• The authors' conclusion: The authors concluded that, wherever possible, the diaphragm muscle should be preserved, even if part of it has to be removed, and a prosthetic patch avoided, as long as all visible tumour is still removed. They wrote that this strategy was justified by better outcomes around the time of surgery without compromising overall survival.
• Limitations the authors state:
  • The number of patients was relatively small.
  • Because of the small numbers, a real difference could have been missed (type II error), and the analyses are less reliable.
  • Leaving patients with chylothorax out of the hospital-stay analysis may have distorted the comparison.
  • The better performance status (general fitness score) in the PD group is, in the authors' view, a subjective assessment.

Topics

Medical terms in this study, explained in our Lexicon: Diaphragm, Pleural Mesothelioma, Pleurectomy/Decortication (P/D), Pleura, Overall Survival, Median Overall Survival.

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• How successful is lung-preserving radical surgery in the mesothelioma and radical surgery-trial environment? A case-controlled analysis — Y. Shahin, J. Wellham, et al. (2011)
• Ki67 Tumor Expression Predicts Treatment Benefit Achieved by Macroscopic Radical Lung-Preserving Surgery in Pleural Mesothelioma-A Retrospective Multicenter Analysis — S. Hintermair, S. Iser, et al. (2024)
• The management of the diaphragm during radical surgery for malignant pleural mesothelioma — A.J. Sharkey, R. Bilancia, et al. (2016)
• Long-term Survival and Propensity Score Matched Outcomes of Bilateral vs. Unilateral Diaphragm Interventions in Cytoreductive Surgery plus Intra-peritoneal Chemotherapy — B. Singh, G. Singh, et al. (2018)
• Extra-pleural pneumonectomy versus no extra-pleural pneumonectomy for patients with malignant pleural mesothelioma: clinical outcomes of the Mesothelioma and Radical Surgery (MARS) randomised feasibility study — T. Treasure, L. Lang-Lazdunski, et al. (2011)

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