Professor Special Lecture: 71st Annual Meeting of the Medical Society of Toho University Biological and Clinicopathological Features of Pulmonary Large-cell Neuroendocrine Carcinoma-A New Era of Research

Large-cell neuroendocrine carcinoma (LCNEC) of the lung, categorized as a lung neuroendocrine tumor, shows clinicopathological features similar to those of small-cell lung carcinoma (SCLC), although there are some differences between them. As patients with LCNEC have a very poor prognosis, and surgery alone does not provide a cure for it, a new treatment strategy including adjuvant chemotherapy after surgery is needed. Several studies have compared the biological behaviors of LCNEC and SCLC, which, in addition to their clinicopathological features, are very similar. Recently, the biological features of LCNEC related to molecular targeted therapies have been investigated, and new treatment strategies, such as mTOR (mammalian target of rapamycin) inhibitors, have been proposed for patients with LCNEC. Here, I discuss the current biological and clinicopathological features of LCNEC and introduce recent new research on it. LCNEC was reclassified from a variant of large-cell carcinoma to a neuroendocrine tumor. Consequently, the focus of studies on LCNEC switched from clinicopathological features to molecular targeted therapies, and research on LCNEC entered a new era. Further studies are needed to improve the prognoses of patients with LCNEC.