gms | German Medical Science

Objective: Immunotherapy has revolutionized cancer treatment by improving patient outcome and decreasing therapy-associated morbidity. Immune checkpoint inhibitors have been designed to target programmed death-ligand 1 (PD-L1) and its receptor, programmed death-1 (PD-1). These agents have shown promise in non-small cell lung carcinoma (NSCLC), leading to their FDA/EMA approval to treat this condition in 2017. To date, no characterization of PD-L1 status in brain metastases (BM) from NSCLC has been performed. As BM represent a unique entity in cancer biology and often pose a therapeutic challenge, determining whether or not they might be amenable to immunotherapy becomes extremely important.

Methods: We retrospectively analyzed the PD-L1 status of patients undergoing resection of NSCLC BM at our center between January 2017 and July 2018. PD-L1 status was determined by means of immunohistochemistry with 28-8 antibody on the Dako-OMNIS platform. These analyses were performed at the institute for molecular pathology of our clinic. Statistical analysis was performed with IBM® SPSS® 21.

Results: A total of 36 patients were included in our cohort. The majority were females (n=19) with a mean age of 66 years. PD-L1 expression was seen in n=17 (47.2%). No statistically significant difference between amount of brain lesions, systemic disease burden, and time to brain progression was observed. The effect on overall survival remains to be assessed, when sufficiently long follow-up is available.

Conclusion: We report the largest series on PD-L1 expression in NSCLC BM. In our cohort, this is relatively common. Molecular pathological analyses should be routinely performed in BM samples, as they can reveal whether or not a patient might be amenable to tailored, less morbid therapy in the era of personalized medicine.