Combined small-cell lung carcinoma (c-SCLC)
Small-cell lung carcinoma can occur in combination with a wide variety of other histological variants of lung cancer, including extremely complex malignant tissue admixtures. When it is found with one or more differentiated forms of lung cancer, such as squamous cell carcinoma or adenocarcinoma, the malignant tumor is then diagnosed and classified as a combined small cell lung carcinoma (c-SCLC). C-SCLC is the only currently recognized subtype of SCLC.Although combined small-cell lung carcinoma is currently staged and treated similarly to "pure" small-cell carcinoma of the lung, recent research suggests surgery might improve outcomes in very early stages of this tumor type.Smoking is a significant risk factor. Symptoms and signs are as for other lung cancers. In addition, because of their neuroendocrine cell origin, small-cell carcinomas will often secrete substances that result in paraneoplastic syndromes such as Lambert–Eaton myasthenic syndrome. Extrapulmonary small-cell carcinoma
Very rarely, the primary site for small-cell carcinoma is outside of the lungs and pleural space; in these cases, it is referred to as extrapulmonary small-cell carcinoma (EPSCC). Outside of the respiratory tract, small-cell carcinoma can appear in the cervix, prostate, liver, pancreas, gastrointestinal tract, or bladder. It is estimated to account for 1,000 new cases a year in the U.S. Histologically similar to small-cell lung cancer, therapies for small-cell lung cancer are usually used to treat EPSCC. First-line treatment is usually with cisplatin and etoposide. In Japan, first-line treatment is shifting to irinotecan and cisplatin.
Responses in ES-SCLC are often of short duration, and the evidence surrounding the risk of treatment compared to the potential benefit of chemotherapy for people who have extensive SCLC is not clear.If complete response to chemotherapy occurs in a subject with SCLC, then prophylactic cranial irradiation (PCI) is often used in an attempt to prevent the emergence of brain metastases. Although this treatment is often effective, it can cause hair loss and fatigue. Prospective randomized trials with almost two years of follow-up have not shown neurocognitive ill-effects. Meta-analyses of randomized trials confirm that PCI provides significant survival benefits.In August 2018, the FDA approved nivolumab to treat patients with metastatic small cell lung cancer (SCLC) who failed to respond to platinum-based chemotherapy and at least one other line of treatment. Nivolumab is approved in more than 60 countries. According to LUNGevity Foundation, “This approval marks a major milestone for the patients touched by this unrelenting disease and may motivate them to pursue further treatment where there previously were no other approved options.”In September 2018, the results from the global, randomized phase I/III IMpower 133 trial were announced at the World Congress on Lung Cancer in Toronto, ON. In this study, patients with ES-SCLC were treated with standard carboplatin plus etoposide and were randomized to receive atezolizumab or placebo. Atezolizumab was associated with a significant improvement in overall survival (HR for death = 0.70)

Signs and symptoms
Small-cell carcinoma of the lung usually presents in the central airways and infiltrates the submucosa leading to narrowing of bronchial airways.