Successful Treatment of Combined Large Cell Neuroendocrine Carcinoma Harboring an EGFR Mutation with EGFR-TKIs plus Bevacizumab: A Case Report

Large cell neuroendocrine carcinoma (LCNEC) of the lung with epidermal growth factor receptor (EGFR) mutation is rare, and few cases have been treated with EGFR tyrosine kinase inhibitors (TKIs). We report the treatment of combined LCNEC with adenocarcinoma harboring an EGFR mutation with EGFR-TKIs and bevacizumab. Our patient was a 70-year-old asymptomatic woman who underwent surgical resection of the lung for combined LCNEC with adenocarcinoma harboring an activating EGFR mutation 11 months previously. Magnetic resonance imaging (MRI) and positron emission tomography revealed metastatic lesions in the brain and lung. The patient was diagnosed with recurrence of combined LCNEC with adenocarcinoma. The brain lesion was irradiated, followed by administration of afatinib. Eight months after irradiation, brain MRI revealed ringed enhancement and perilesional edema after radiotherapy without new metastatic lesions. We switched treatment to erlotinib and bevacizumab, resulting in maintenance of stable disease for 10 months. Overall, the disease was controlled for 18 months with EGFR-TKIs and bevacizumab. Combination treatment with EGFR-TKIs and bevacizumab could be a treatment option for LCNEC of the lung harboring EGFR mutations, especially with brain metastasis.