Abstract 1289P
Background
Immune checkpoint inhibition (ICI) is standard therapy for NSCLC patients alone or in combination with chemotherapy, but little data on the effect of ICI in patients with untreated BM exist. Consequently, the actual incidence of BM in real-life NSCLC patients eligible for ICI need further investigation as does the rate of ICR to ICI.
Methods
A prospective study (NCT03870464) was conducted in advanced NSCLC patients initiating ICI during April 1st 2018 and April 31st 2021. Patients eligible for ICI were offered magnetic resonance imaging (MRI) of the brain prior to or shortly after first ICI (within one week). In cases of BM, an individual assessment was made based on symptoms, size, number and anatomic location of BM with shared decision of whether to give radiotherapy (RT) prior to ICI. To evaluate ICR, a MRI of the brain was performed after 8-9 weeks of ICI, with modified RECIST criteria for evaluation.
Results
177 patients were eligible, baseline MRI of the brain was performed in 89% (n=157). Of those 157 patients, 27% (n=43) had BM and for 20% (n=31) this finding was new. The number of BM in this group was: 1 (n=14; 45.2%), 2 (n=6; 19.4%), 3 (n=2; 6.5%) and ≥ 4 (n=9, 29%). Females had a higher incidence of BM than men, and all patients diagnosed with BM had adenocarcinoma. Newly diagnosed BM on MRI lead to RT prior to ICI in 32% (10/31) with the majority having stereotactic RT. For patients with no RT prior to their first ICI (n=21), five patients were treated with RT/and or surgery after the first ICI (not due to clinical progression) and were not evaluable. Two patients have not reached MRI evaluation yet. Five patients had verified ICI induced ICR (complete response: n=1, partial response n=4), and yet another five had stable intracranial disease (SD). Three had progressive disease and one died prior to MRI evaluation. Of evaluable patients 5/14 (36%) had verified ICR and another 36% had SD.
Conclusions
In our study, 20% of NSCLC patients had undiagnosed BM at the time of first ICI. Rate of ICR in patients with untreated BM was 36% and yet another 36% had SD. Data on duration of ICR, outcome and quality of life in these patients is needed in order to optimize treatment for NSCLC patients diagnosed with BM.
Clinical trial identification
NCT03870464.
Editorial acknowledgement
Legal entity responsible for the study
B. Bjørnhart.
Funding
University of Southern Denmark, The Department of Radiology OUH, The Region of Southern Denmark.
Disclosure
All authors have declared no conflicts of interest.