Small Cell Lung Cancer

November 27, 2020

3 min read

Cancer is named for the location in the body when it starts, and small cell lung cancer (SCLC) starts in the lungs. Lung cancers are the second most common type of cancer among U.S. residents according to the National Organization for Rare Disorders. About 30,000 to 35,000 new people are diagnosed with small cell lung cancer each year in the U.S., representing 10% to 15% of all people with lung cancer, the National Organization for Rare Disorders reports.

Main types of small cell lung cancer (SCLC)

The National Cancer Institute reports there are two types of small cell lung cancer, oat cell cancer and combined small cell carcinoma. Carcinoma is another term for cancer. The difference between the types can be seen when the lung cancer cells are viewed under a microscope. Combined small cell carcinoma (C-SCLC) is less common than oat cell cancer. It represents between 5% and 28% of the small cell lung cancers that are diagnosed, according to the World Health Organization.

Small cell lung cancer risks

Tobacco smoking is the primary risk factor for small cell lung cancer. Smoking any kind of tobacco, including cigarettes, pipes, and cigars, can be a risk factor. Second-hand smoke exposure can also lead to SCLC.

Additional risk factors include exposure to the following environments or substances:

Asbestos or other workplace hazards including soot and tar
Metals including arsenic, chromium, beryllium, and nickel
Radiation exposure, including radiation therapy, radon, imaging tests, and nuclear explosions
Air pollution
HIV infection
Family history of lung cancer

Tobacco smoking combined with other factors increases the risk of SCLC, according to the National Cancer Institute. The earlier a person began smoking tobacco, the longer they smoked, and the more they smoked, the greater the risk.

Symptoms of small cell lung cancer

Small cell lung cancer symptoms are primarily related to breathing, but also include other general cancer symptoms. They include:

Chest pain or discomfort
Cough that doesn't go away and may worsen over time
Trouble breathing
Wheezing
Coughing up bloody sputum or mucus
Hoarseness and trouble swallowing
Loss of appetite
Weight loss with no apparent cause
Persistent tiredness
Facial swelling

Small cell lung cancer diagnosis and staging

Clinicians will use a physical exam and health history first, and then use imaging tests and laboratory tests to determine if cancer is present, and if it's small cell lung cancer. Imaging tests can include X-rays and CT or CAT scans. Images of the brain and other organs can also be used to determine the stage of cancer.

Biopsies take cells from suspected cancer tissue and examine them for the presence of cancer. FNA biopsies, or fine-needle aspiration, removes tissue from the lung using a fine needle. A bronchoscopy uses a thin tube and a camera to visually examine lung passages for cancer. Other physical biopsy techniques include thoracoscopy, thoracentesis, and mediastinoscopy.

Light and electron microscopy can examine suspected cancer cells in high detail. Immunohistochemistry are lab tests that examine antibodies in tissue that result from cancer, and that also can differentiate one type of cancer from another.

Staging in cancer refers to the stage of development of cancer within the body. Small cell lung cancer has two stages: limited-stage small cell lung cancer and extensive-stage small cell lung cancer. The degree of development determines treatment plans and prognosis.

Metastasis of small cell lung cancer

While some cancers spread slowly, small cell lung cancer metastasizes, or spreads throughout the body. If the cancer spreads to other organs such as the brain, it is still small cell lung cancer -- not brain cancer. Cancer cells can spread through the lymphatic system and the circulatory system, i.e. through the lymph and/or blood.

Treatment of small cell lung cancer

Small cell lung cancer can be treated. There are six standard types of treatment, according to the National Cancer Institute:

Surgery
Radiation therapy
Chemotherapy
Immunotherapy
Laser therapy
Endoscopic stent placement

Some treatments do cause side effects, including radiation therapy and chemotherapy. Clinical trials are also available for SCLC, and the National Cancer Institute advises people diagnosed with small cell lung cancer to consider participating in a clinical trial.