S73 Brain imaging in the management of people with lung cancer prior to therapy with curative intent: multi-centre review of the assumptions made in the NICE guideline NG122 evidence review

Introduction In March 2019, NICE published a lung cancer update evidence review (NICE Guideline NG122) recommending brain imaging for those patients who have stage II or III non-small cell lung cancer prior to treatment with curative intent. We present a multi-centre retrospective review of real world data, looking at the prevalence of brain metastases in our lung cancer cohort. We review the impact on management and compare it with the assumptions made in the economic modelling from the NICE Guideline. Methods Consecutive patients with clinical stage II and stage III lung cancer in the calendar year 2018 (01/01/2018 – 31/12/2018) from 11 acute trusts across the UK were retrospectively reviewed. Patients who had brain imaging as part of their investigations pre-treatment were reviewed to see the impact on radical management. Data was collected on those who presented with brain metastases within 6 months of treatment, who had not previously undergone brain imaging. Patients who died within 6 months of treatment were excluded. Results Data from 579 patients was analysed. Overall the prevalence of brain metastases was 5.5% (10/182) in stage II disease (Pre-treatment cohort 2% (1/51), post-treatment cohort 6.9% (9/131)) versus NICE model prevalence 9.5% (14/161). The prevalence was 6.3% (25/397) in stage III disease (Pre-treatment cohort 4.8% (11/227), post-treatment cohort 8.2% (14/170)) versus NICE model prevalence 9.3% (11/123). Table 1 compares outcomes for the pre-imaged cohort to the data from NG122. Discussion Our large data set from 11 Trusts across the UK demonstrates the prevalence of brain metastases in stage II and III lung cancer is lower than that used in the economic modelling from NICE. We show that 30% of stage III patients who have brain metastases on pre-treatment imaging continue to undergo radical lung cancer treatment (NICE assumption 0%). A much higher percentage of stage III patients undergo brain specific treatments than was assumed in NICE economic model, even when treatment intent is changed to palliative. This data strengthens the argument to consider re-examining the economic analysis with real-world data.