Monotherapy with pembrolizumab in the first-line treatment of non-small cell lung cancer with a high expression of PD-L1 ≥ 50 %

Abstract

The current approach to treatment selection in a patient with metastatic non-small cell lung cancer (NSCLC) is personalized. It is based on the histological subtype of NSCLC (squamous, non-squamous), the result of tumour PD-L1 expression, and, in non-squamous histology, on the result of genetic testing, i.e. EGFR, ALK, ROS1, and BRAF mutations. In tumours with a high expression of PD-L1 ≥ 50% (and in adenocarcinomas in the absence of sensitive mutations), treatment with immunotherapy with pembrolizumab is preferred in the first line. The authors report a case of a patient with generalized lung adenocarcinoma treated with pembrolizumab in whom a partial response to treatment was observed. At the same time, however, neurological symptoms developed, primarily suspected to be an adverse reaction to immunotherapy. According to a brain MRI scan, the findings were evaluated to be most likely vasogenic oedema following stereotactic radiotherapy of the brain metastases. The authors discuss the issue of diagnosing and managing potential adverse events during the time of the COVID-19 pandemic.