Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a type of lung cancer that is different from other lung cancers. It accounts for about 13 percent of all lung cancers.

SCLC first appears in locations around or near the bronchi (breathing tubes) inside the lungs. SCLC is an aggressive type of lung cancer and typically invades the bronchial mucosal layer (a layer of tissue in the breathing tubes). Because it grows quickly, SCLC tends to spread early to distant body sites (metastasis). This is why treatment is critical to slow the spread 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:2

  • Small cell carcinoma (also called oat cell cancer)
  • Combined small cell carcinoma

SCLC tends to respond well to chemotherapy and radiation.

Staging of small cell lung cancer

Small cell lung cancer is graded in 2 stages. These stages describe the size and spread of the cancer and include:1,2

  • Limited stage means the SCLC is found on only 1 side of the chest and involves just 1 part of the lung and/or the lymph nodes on that side. About 30 percent of patients diagnosed with SCLC have limited stage disease.
  • Extensive stage means the SCLC has spread to the other lung, lymph nodes on the other side of the chest, or to distant organs. About 70 percent of SCLC cases are found at this stage.

Risk factors for small cell lung cancer

Risk factors are anything that increases the chances that you will get a disease. The main risk factors for lung cancer are:3

  • Smoking cigarettes, pipes, or cigars now or in the past.
  • Being exposed to secondhand smoke at home or work.
  • Being exposed to asbestos, arsenic, chromium, beryllium, nickel, soot, or tar at work.
  • Being exposed to radiation to the breast or chest during tests like CT scans.
  • Being exposed to radon gas at home or work.
  • Living in a place with air pollution.
  • Having a family history of lung cancer.
  • Having an HIV infection.
  • Taking beta carotene supplements while being a heavy smoker.

As with most cancers, getting older is an important risk factor. Most lung cancers are diagnosed in people 65-74 years of age.2

Symptoms of small cell lung cancer

Lung cancer may create many symptoms that send you to the doctor for answers. It is sometimes found by accident when someone gets a chest x-ray. The most common symptoms of SCLC include:3

  • Chest pain
  • A cough that does not go away
  • Trouble breathing
  • Wheezing
  • Blood in sputum (mucus coughed up from the lungs)
  • Hoarseness
  • Trouble swallowing
  • Loss of appetite
  • Weight loss for no known reason
  • Fatigue (feeling very tired)
  • Swelling in the face or the veins in the neck

Diagnosing small cell lung cancer

Several tests may be needed to diagnose SCLC. The most common include:3

  • Physical exam to check for lumps or other signs that can be seen or felt
  • Review of health history including history of smoking and past jobs
  • Lab tests for tissue, blood, sputum, and urine
  • Chest x-ray
  • CT scan
  • Biopsy (when a small sample of tissue or fluid from the lung is removed and tested)
  • Bronchoscopy (a camera that looks down the throat)
  • Thoracoscopy, thoracentesis, or mediastinoscopy (surgeries that allow a doctor to look for cancer cells or gather samples to test for cancer cells)
  • Antibody and molecular testing
  • Pulmonary function test

Treatment for small cell lung cancer

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

Radiation or surgery may also be recommended, depending on the stage of the cancer and the person’s overall health. SCLC is highly sensitive to radiation, and radiation therapy can improve survival rates. There are new, groundbreaking treatment developments being made for patients living with SCLC. Surgery is rarely used in SCLC but may be recommended in cases where the cancer is contained to one lung and the nearby lymph nodes.1-3

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Written by: Emily Downward & Jessica Johns Pool | Last reviewed: July 2020.