Lung cancer is the most common cancer in men and women. The main cause of most cases of lung cancer is the consumption of tobacco products. A small fraction of lung cancer is caused by substances that are inhaled during work, such as asbestos and nickel. SCLC accounts for 20% of lung cancer. Primary, patients with SCLC are treated with chemotherapy because it is well-sensitive to chemotherapy and at the time of diagnosis SCLC is usually augmented through the body. SCLC is divided into limited-stage and extensive-stage. Limited stage SCLC is confined to one hemithorax and extended stage in SCLC is extended beyond one hemithorax. Surgery doesn't have an important role in the treatment of SCLC because most times SCLC is detected in the extended stage. In patients with limited-stage disease, chemotherapy with radiation therapy is performed simultaneously, while in patients with an extended stage only chemotherapy is carried out. The most commonly used combination of cytotoxic drugs is etoposide and cistplatin. Chemotherapy is carried out between 4 to 6 cycles. SCLC tends to spread to the brain, so most patients get prophylactic brain radiation to prevent metastases in the brain. In most patients a relapse of SCLC appears. Topotecan is the drug of choice in the treatment of relapse SCLC. The prognosis is very poor, the survival rate in those with the limited stage is 20 months, and in patients with extended stage, it's between 7 and 11 months.