Evaluating quality of life and cost implications of prophylactic radiotherapy in mesothelioma: Health economic analysis of the SMART trial

Our plain-English summary of Evaluating quality of life and cost implications of prophylactic radiotherapy in mesothelioma: Health economic analysis of the SMART trial, by S.A. Stewart, A.O. Clive, N.A. Maskell, et al (PloS One, 2018).

The study

• Authors: S.A. Stewart, A.O. Clive, N.A. Maskell, E. Penz
• Journal: PloS One
• Published: 2018;13(2):e0190257
• Type of article: Randomized trial
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The SMART trial is a UK-based, multicentre RCT comparing prophylactic radiotherapy and symptom-based (deferred) radiotherapy in 203 patients with Malignant Pleural Mesothelioma who had undergone large bore pleural interventions. Using costs and quality of life data collected alongside the clinical trial, we will estimate the cost-effectiveness of prophylactic radiotherapy compared to deferred radiotherapy over a 1-year period.

Methods: Healthcare utilization and costs were captured during the trial. Utility weights produced by the EQ-5D questionnaire were used to determine quality-adjusted life-years (QALY) gained. The incremental cost-effectiveness ratio was calculated over the one-year trial period.

Results: Costs were similar in the immediate and deferred radiotherapy groups: £5480.40 (SD = £7040; n = 102) and £5461.40 (SD = £7770; n = 101) respectively. There was also no difference in QALY: 0.498 (95% CI: [0.45, 0.547]) in the prophylactic radiotherapy group versus 0.525 (95% CI: [0.471, 0.580]) in the deferred group. At a willingness to pay threshold of £30,000/QALY there was only a 24% chance that prophylactic radiotherapy was cost-effective compared to deferred radiotherapy.

Conclusions: There was no significant effect of prophylactic radiotherapy on quality of life in the intervention group, nor was there any discernable decrease in healthcare costs. There is little evidence to suggest that prophylactic radiotherapy is a cost-effective intervention in this population.

Trial Registration: ISRCTN72767336 with ISRCTN.

In plain English

This was a health economic analysis carried out alongside the SMART trial, which randomised 203 patients with malignant pleural mesothelioma at 22 UK hospitals after large-bore pleural procedures. Patients received either immediate (prophylactic) radiotherapy to the procedure site, or radiotherapy only if the cancer grew along the procedure tract. Over one year, mean health service costs were £5480.40 in the prophylactic group and £5461.40 in the deferred group, with no significant difference. Quality-adjusted life-years were 0.498 (95% confidence interval 0.450 to 0.547) in the prophylactic group and 0.525 (0.471 to 0.580) in the deferred group. The authors described this difference as small, with a confidence interval that covered zero. The chance that prophylactic radiotherapy was cost-effective at £30,000 per quality-adjusted life-year was 31% by mean-cost analysis and 49% by median-cost analysis; the abstract instead gives 24%. In a survival model, neither treatment group nor having a tract metastasis showed an effect on survival. The authors concluded that prophylactic radiotherapy is unlikely to be cost-effective. They noted the one-year time frame and that the study was not necessarily powered to detect cost differences.

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: Cost-effectiveness (health economic) analysis from the healthcare payer's perspective, carried out alongside a multi-centre, open-label, phase 3 randomised controlled trial (SMART)
• Who was studied: 203 patients from 22 UK hospitals with confirmed malignant pleural mesothelioma who had large-bore pleural interventions in the 35 days before recruitment; 102 in the prophylactic radiotherapy group and 101 in the deferred group; 89% male
• Exposure: Not an asbestos exposure study. The intervention compared immediate (prophylactic) radiotherapy to pleural intervention sites with deferred radiotherapy, which was given only if a procedure-tract metastasis developed
• Main results:
  • Mean healthcare cost over the trial period was £5480.40 (SD 7040) in the prophylactic radiotherapy group and £5461.40 (SD 7770) in the deferred radiotherapy group, with no significant difference
  • Mean QALY was 0.498 (bootstrapped 95% CI 0.450 to 0.547) in the prophylactic radiotherapy group and 0.525 (95% CI 0.471 to 0.580) in the deferred radiotherapy group
  • The authors cautioned that the QALY difference between groups was small and its bootstrapped confidence interval covered zero
  • At a willingness-to-pay threshold of £30,000 per QALY, the probability that prophylactic radiotherapy was cost-effective compared to deferred radiotherapy was 31% using mean-cost analysis and 49% using median-cost analysis
  • Patients with a procedure-tract metastasis (n=25) had slightly higher mean QALY (0.518) and slightly lower mean costs (£4,911.69) than those without (n=178; 0.509 and £5,549.47); the differences were not statistically significant
  • In a Cox model, the hazard ratio for survival was 0.96 (95% CI 0.7 to 1.4) for deferred compared with prophylactic radiotherapy, and 0.99 (95% CI 0.6 to 1.8) for patients with a procedure-tract metastasis compared with those without
• The authors' conclusion: The authors concluded that immediate prophylactic radiotherapy is unlikely to be cost-effective compared to deferred radiotherapy for preventing procedure-tract metastases in patients with malignant mesothelioma undergoing pleural procedures
• Limitations the authors state:
  • The study lasted one year and close to half the patients were still alive at one year, so later health outcomes may have been missed
  • The UK single-payer costs may not apply to other countries
  • The costs of the chemotherapy drugs themselves were not included because data on the specific drugs and doses were insufficient
  • This was a secondary analysis that was not necessarily powered to detect meaningful cost differences

Topics

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

Medical terms in this study, explained in our Lexicon: Quality of Life, Mesothelioma, Pleural Mesothelioma, Clinical Trial.

Related studies

• Protocol for the surgical and large bore procedures in malignant pleural mesothelioma and radiotherapy trial (SMART Trial): an RCT evaluating whether prophylactic radiotherapy reduces the incidence of procedure tract metastases — A.O. Clive, P. Wilson, et al. (2015)
• Prophylactic radiotherapy for the prevention of procedure-tract metastases after surgical and large-bore pleural procedures in malignant pleural mesothelioma (SMART): a multicentre, open-label, phase 3, randomised controlled trial — A.O. Clive, H. Taylor, et al. (2016)
• A multicentre non-blinded randomised controlled trial to assess the impact of regular early specialist symptom control treatment on quality of life in malignant mesothelioma (RESPECT-MESO): study protocol for a randomised controlled trial — S. Gunatilake, F.J. Brims, et al. (2014)
• Assessing quality of life when planning and evaluating worker notification programs: two case examples — B.E. Meyerowitz (1993)
• The effect of chemotherapy on health-related quality of life in mesothelioma: results from the SWAMP trial — D.T. Arnold, C.E. Hooper, et al. (2015)
• Satisfactory results of a psychometric analysis and calculation of minimal clinically important differences of the World Health Organization quality of life-BREF questionnaire in an observational cohort study with lung cancer and mesothelioma patients — M. de Mol, S. Visser, et al. (2018)

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