Complete Remission of Multiple Brain Metastases in a Patient with EGFR-Mutated Non-Small-Cell Lung Cancer Treated with First-Line Osimertinib without Radiotherapy

Abstract

Osimertinib has demonstrated efficacy against stable or asymptomatic central nervous system (CNS) metastases of epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) in phase 2 and 3 clinical trials that allowed prior CNS radiotherapy. However, the efficacy of osimertinib only or the optimal treatment combination or sequence of radiotherapy has not been investigated. A 74-year-old woman diagnosed with T4N1M1c Stage IVB lung adenocarcinoma with EGFR mutation presented with a left upper lobe mass and multiple bilateral lung metastases. A total of more than 20 asymptomatic multiple brain metastases with a maximum diameter of 12 mm were diagnosed simultaneously. Osimertinib was administered as first-line treatment. Whole brain radiotherapy was deferred because she had no neurological symptoms. After 5 weeks, the multiple brain metastases disappeared completely, together with the response in the lung lesions. This case demonstrated that first-line treatment with osimertinib could even achieve complete remission of multiple brain metastases comprising as many as twenty lesions of EGFR-mutated NSCLC without radiation therapy. Radiation therapy for brain metastases can be deferred or even withheld. A new treatment strategy for EGFR mutated NSCLC with CNS metastases should be investigated using osimertinib, especially regarding optimal combination or sequence of radiotherapy.

Figure 1

The patient was diagnosed with T4N1M1c Stage IVB lung adenocarcinoma with EGFR exon 19 deletion mutation presenting as (a) 40 mm wide shadows in the upper lobe of the left lung and (b) multiple bilateral small nodules in the entire lung field.

Figure 2

Multiple asymptomatic brain metastatic lesions (more than 20 in total) with a maximum diameter of 12 mm were detected by gadolinium-enhanced MRI at the first diagnosis (a–d). After 5 weeks, the multiple brain metastases had disappeared completely on contrast-enhanced brain MRI (e–h). Complete CNS response was confirmed.