Health economic evaluation of a serum-based blood test for brain tumour diagnosis: exploration of two clinical scenarios

Abstract

Objectives: To determine the potential costs and health benefits of a serum-based spectroscopic triage tool for brain tumours, which could be developed to reduce diagnostic delays in the current clinical pathway.

Design: A model-based health pre-trial economic assessment. Decision tree models were constructed based on simplified diagnostic pathways. Models were populated with parameters identified from rapid reviews of the literature and clinical expert opinion.

Setting: Explored as a test in both primary and secondary care (neuroimaging) in the UK health service, as well as application to the USA.

Participants: Calculations based on an initial cohort of 10 000 patients. In primary care, it is estimated that the volume of tests would approach 75 000 per annum. The volume of tests in secondary care is estimated at 53 000 per annum.

Main outcome measures: The primary outcome measure was quality-adjusted life-years (QALY), which were employed to derive incremental cost-effectiveness ratios (ICER) in a cost-effectiveness analysis.

Results: Results indicate that using a blood-based spectroscopic test in both scenarios has the potential to be highly cost-effective in a health technology assessment agency decision-making process, as ICERs were well below standard threshold values of £20 000-£30 000 per QALY. This test may be cost-effective in both scenarios with test sensitivities and specificities as low as 80%; however, the price of the test would need to be lower (less than approximately £40).

Conclusion: Use of this test as triage tool in primary care has the potential to be both more effective and cost saving for the health service. In secondary care, this test would also be deemed more effective than the current diagnostic pathway.

Keywords: adult oncology; biophysics; health economics; neurological oncology; neurology.

Figure 1

The diagnostic pathway of brain tumours. Timings relate to the diagnosis of high-grade gliomas and are based on discussion with the Clinical Focus Team and Aggarwal et al. GP, general practitioner; MDT, multidisciplinary team; OPD, outpatient department.

Figure 2

Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopic test of blood serum for the diagnosis and stratification of brain tumours using machine learning algorithms.

Figure 3

An unprocessed spectrum derived from human blood serum using attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. Spectral regions correspond to known bond vibrations and can therefore be associated with groups of biomolecules such as protein, lipid, phosphate and carbohydrates. Broad examples of blood serum constituents are listed.

Figure 4

A decision tree model describing the integration of a serum spectroscopy test in the current diagnostic pathway, and the effect on MRI/CT imaging for suspected brain tumour. D1, 1 week; D2, 4 weeks; D3, 8 weeks; LY, life-year; S(t|D), survival time in days conditional on ‘delay’.

Figure 5

Incremental cost-effectiveness ratios (ICER) at various specificities in primary care (‘Scenario 1’). The £30 000 ICER threshold is displayed as a dashed horizontal line. QALY, quality-adjusted life-year.

Figure 6

Incremental cost-effectiveness ratios (ICER) at various specificities in secondary care (‘Scenario 2’). The £30 000 ICER threshold is displayed as a dashed horizontal line. QALY, quality-adjusted life-year.

Figure 7

Cost-effectiveness acceptability curve (CEAC) at £50 and £100 per test—primary care (‘Scenario 1’). QALY, quality-adjusted life-year.

Figure 8

Cost-effectiveness acceptability curve (CEAC) at £50 and £100 per test—secondary care (‘Scenario 2’). QALY, quality-adjusted life-year.