1110P - Follow-up brain imaging in patients with melanoma brain metastasis and immune checkpoint inhibitors

Background

More than 50% of patients with advanced melanoma are eventually diagnosed with brain metastasis (BM). Immune checkpoint inhibitors (ICI) can induce durable responses in BMs and have improved survival of patients with BM. For monitoring BM, magnetic resonance imaging (MRI) is performed in long-term survivors of BM, while this may be redundant and cause unnecessary clinical dilemmas. The objective of this study was to assess the clinical impact of follow-up (FU) MRI in patients who are treated with ICI for melanoma BM and are without intracranial progressive disease (PD) >1 year after start of ICI.

Methods

A single-center, retrospective, cohort study was performed at the Erasmus MC, Rotterdam, the Netherlands, which is a large tertiary referral center for patients with melanoma. Consecutive patients with melanoma who started with first-line ICI (2012 - 2022) for the treatment of BM were included. Patients without FU MRI were excluded. We selected patients without intracranial PD at 1 year after start of ICIs, according to RANO-BM criteria. In this subgroup, we assessed intra- and extracranial disease status according to RANO-BM and RECISTv1.1 respectively, and the number of FU MRIs with clinical impact, defined as change in treatment strategy.

Results

70 patients were identified who had a total of 172 BMs and, one year after start of ICI, 34 (49%) patients were without intracranial progression. In these 34 patients, best intracranial response was complete response, partial response and stable disease in 29%, 44% and 27% respectively. During a median imaging FU of 35.1 months (IQR 22.2 – 43.4), 10 (29%) of 34 patients had PD: intracranially (9%), extracranially (17%), or both intra- and extracranially (3%). During this FU period, starting at 1-year after the start of ICIs, 34 patients underwent a total of 254 MRI scans and 3% of these scans had clinical impact, leading to local treatment, other systemic treatment or supportive care.

Conclusions

The clinical impact of FU MRI seems limited in patients with melanoma who are without progressive BMs >1 year after start of ICIs. Therefore, use of MRI could be reconsidered for long-term FU of BMs with a favorable response after ICI.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Daniel Den Hoed Foundation.

Disclosure

M. Smits: Financial Interests, Institutional, Other, Consultancy: Bracco. A.A.M. Van der Veldt: Financial Interests, Institutional, Other, Consultancy: BMS, MSD, Merck, Sanofi, Pierre Fabre, Roche, Novartis, Pfizer, Eisai, Ipsen. All other authors have declared no conflicts of interest.