Diagnosis and treatment of neuroendocrine lung tumors.

Pulmonary neuroendocrine tumors (PNT) encompass a broad spectrum of tumors including typical carcinoid (TC) and atypical (AC) tumors, large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC). Although no variety can be considered benign, AC and TC have a much lower metastatic potential, are usually diagnosed in early stages, and most are candidates for surgical treatment. Several chemotherapy (CT) regimens are available in the case of recurrence or in advanced stages, although scientific evidence is insufficient. LCNEC, which is currently classified alongside large-cell carcinomas, have molecular features, biological behavior and CT sensitivity profile closely resembling SCLC. Pathological diagnosis is often difficult, despite the availability of immunohistochemical techniques, and surgical specimens may be necessary. The diagnostic tests used are similar to those used in other lung tumors, with some differences in the optimal tracer in positron emission tomography. The new TNM classification is useful for staging these tumors. Carcinoid syndrome, very rare in PNT, may cause symptoms that are difficult to control and requires special therapy with somatostatin analogs and other drugs. Overall, with the exception of SCLC, new trials are needed to provide a response to the many questions arising with regard to the best treatment in each lineage and each stage.