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.²

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 at first, but it often comes back after treatment.^1,3

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:^1-3

• Limited stage means the SCLC is found in the lung where it started and may have spread to the area between the lungs or to the lymph nodes above the collarbone. About 30 to 40 percent of patients diagnosed with SCLC have limited stage disease.
• Extensive stage means the SCLC has spread beyond these areas to other parts of the body, such as the other lung or distant organs. About 60 to 70 percent of SCLC cases are found at this stage.

Doctors may also use the TNM system, the same staging system used for other lung cancers, to describe SCLC in more detail, especially when surgery or radiation is being considered.^1,3

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, such as radiation therapy to the breast or chest, or imaging 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 or older, and the average age at diagnosis is about 70.²

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
• PET/CT scan
• MRI of the brain (to check whether the cancer has spread to the brain)
• 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

Treatment depends on the stage of the cancer and a person's overall health. Chemotherapy is part of treatment for nearly everyone with SCLC, because SCLC responds well to chemotherapy compared to other types of lung cancer. However, SCLC often comes back after treatment.^1-3

Limited stage

The standard treatment for limited stage SCLC is chemotherapy given at the same time as radiation to the chest (chemoradiation). For some people, immunotherapy may be given afterward to help keep the cancer from coming back.^3,4

Surgery is rarely used in SCLC, but it may be an option when the cancer is small and has not spread to the lymph nodes. Doctors may also discuss radiation to the brain or regular brain MRI scans to watch for spread to the brain.⁴

Extensive stage

For extensive stage SCLC, chemotherapy is usually combined with immunotherapy. Afterward, some people continue treatment to help keep the cancer in check. Radiation may also be used to ease symptoms.^3,4

If the cancer comes back or grows after treatment, other options are available, including newer types of immunotherapy and chemotherapy.⁴

There are new, groundbreaking treatment developments being made for people living with SCLC. Joining a clinical trial may be an option for some people.⁴