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Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a type of lung cancer that is distinct from other lung cancers due to its clinical and biologic characteristics. SCLC comprises 15% of all lung cancers and arises in locations around or near the bronchi (breathing tubes). SCLC is an aggressive subtype of lung cancer and typically invades the bronchial mucosal layer (a layer of tissue in the breathing tubes). A rapidly growing malignancy, SCLC demonstrates early spread to distant body sites (metastasis), and treatment is critical to slow the progression of the disease.1,2

Types of Small Cell Lung Cancer

SCLC has two main sub-types, classified by how the cells look under a microscope: small cell carcinoma (also known as oat cell cancer) and combined small cell carcinoma.2

Staging of Small Cell Lung Cancer

The staging of SCLC, which classifies the size and extent of the cancer, is a two-stage system.

  • Limited stage – A limited stage SCLC is found on only one side of the chest, involving just one part of the lung and/or the lymph nodes on that side. Approximately 30% of patients diagnosed with SCLC have limited stage disease.
  • Extensive stage – An extensive stage SCLC has spread to the other lung, lymph nodes on the other side of the chest, or to distant organs.2,3

Risk Factors for Small Cell Lung Cancer

As with most cancers, increasing age is an important risk factor, and most lung cancers are diagnosed among people 65-74 years of age.4 Other factors that increase the risk of developing SCLC include current or previous tobacco use, exposure to secondhand smoke, occupational exposure to carcinogens (chemicals or substances that can cause cancer), radiation exposure to the breast or chest, family history of lung cancer, or living in an area with high pollution.3

Symptoms of Small Cell Lung Cancer

Lung cancer may produce symptoms or may be found incidentally on chest x-ray. Symptoms result from the location of the primary tumor and may include chest pain, hoarseness, a cough that doesn’t go away, trouble breathing, wheezing, blood in sputum (mucus coughed up from the lungs), trouble swallowing, fatigue, or loss of appetite.3

Treatment for Small Cell Lung Cancer

Chemotherapy is always recommended for SCLC, regardless of the stage, as SCLC is very responsive to chemotherapy as compared to other cell types of lung cancer. Chemotherapy can improve the survival for patients with SCLC but it is rarely curative. Because of the aggressive nature of SCLC, many patients develop metastases (spread of the cancer to other parts of the body).1-3

Besides chemotherapy, treatment recommendations are made based on the stage of the disease and may include radiation or surgery. SCLC is highly sensitive to radiation, and radiation therapy can improve survival rates. Surgery is rarely used in SCLC but may be recommended in cases where the cancer is contained to one lung and the adjacent lymph nodes.1-3

Written by: Emily Downward | Last reviewed: March 2019.
  1. Medscape. Accessed online on 8/4/16 at
  2. American Cancer Society. Accessed online on 8/4/16 at
  3. National Cancer Institute. Accessed online on 8/4/16 at
  4. SEER Cancer Statistics Factsheets: Lung and Bronchus Cancer. National Cancer Institute. Bethesda, MD. Accessed online on 3/29/19 at