There are two primary forms of lung cancer: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Though SCLC is less common than NSCLC, it is more aggressive and rapidly spreads (metastasizes) throughout the body. SCLC accounts for about 15% of all lung cancer diagnoses in the United States each year.

Due to how quickly it grows and spreads, in 60% of SCLC cases the cancer has already metastasized to other areas in the body by the time it is diagnosed. Common sites for metastasis are the lymph nodes, liver, bones, adrenal glands and brain. When SCLC metastasizes, the cancer can cause symptoms that are not typically associated with lung cancer, including bone pain, seizures, confusion and paralysis.

Smoking tobacco is the leading risk factor for SCLC, responsible for 98 percent of all SCLC diagnoses. The best preventive strategy is not to smoke, and if you do, to quit as soon as possible.

Treatments for SCLC include chemotherapy and radiation. Because of the high rate of metastasis, surgery is rarely recommended. In very advanced cases of SCLC, treatments (including chemotherapy and radiation) can be effective in relieving symptoms and improving quality of life.

“Even though SCLC has a tendency to grow quickly, it often shrinks quickly as a response to chemotherapy, radiation therapy, or both,” said Henry Park, MD, MPH, a radiation oncologist in the Department of Therapeutic Radiology. “It is important to see a medical oncologist and radiation oncologist as soon as possible after a diagnosis of SCLC so that treatment can be started right away.”

Like all cancers, SCLC begins at the cellular level and causes abnormal cells in the lungs to reproduce rapidly and uncontrollably. SCLC usually begins in the airways of the lung, and quickly spreads to other areas of your body. SCLC is the most aggressive form of lung cancer. 

There are two primary types of SCLC, named for the affected cell types. They are small cell carcinoma (also known as oat cell cancer) and combined small cell carcinoma. The majority of SCLC cases are small cell carcinomas.

The leading risk for developing SCLC is smoking tobacco. The more you smoke and the earlier in life you began smoking, the greater your risk for SCLC. Other risk factors include exposure to secondhand smoke, workplace carcinogens, radiation and/or environmental pollution, as well as family history of lung cancer and previous HIV infection.

Nearly 25 percent of lung cancer cases do not produce any symptoms. However, symptoms of SCLC, which are also common to all lung cancers, include the following:

• A cough that doesn’t go away or gets worse over time
• Coughing up blood
• Chest pain or discomfort
• Trouble breathing
• Wheezing
• Hoarseness
• Loss of appetite
• Weight loss for no reason
• Fatigue
• Trouble swallowing
• Swelling in the face and/or veins in the neck

If lung cancer is suspected, your doctor will recommend imaging tests (CT, PET or MRI scans) to identify abnormalities in and around your lungs. Your doctor may also take a sample of your mucus to look for cancer cells. If these initial tests identify cancer, a biopsy can be performed by either inserting a needle or making an incision in your chest to remove a small bit of tissue from your lung for further inspection. Another technique doctors commonly use to both visualize and remove lung tissue is called bronchoscopy.   

Your doctor will also determine the extent to which the SCLC has spread throughout your body. This descriptive process, called staging, can help inform treatment. Although numerical stages are used for SCLC as well as for other cancers, SCLC is often classified as either limited-stage disease (LD), where the cancer is confined to a reasonable radiation field within the chest, or extensive-stage disease (ED), where the cancer has spread outside the chest.   

SCLC is rarely detected early. However, with appropriate CT screening for certain patients with a history of smoking, it is occasionally diagnosed before it causes symptoms. Early diagnosis offers the best prognosis for SCLC. 

Most cases of SCLC are treated with chemotherapy and/or radiation therapy because of how quickly the cancer tends to spread. In rare cases of early-detected, limited-stage SCLC, surgery can remove the section of the lung (or lobe) containing cancerous tissue from the body, typically in combination with chemotherapy and/or radiation therapy, described below.

• Chemotherapy uses anticancer drugs. These are administered through injection into the vein, by taking a pill, or through other delivery methods, to kill cancer cells. Chemotherapy is also used to prolong survival and treat symptoms of SCLC.
• Radiation therapy uses high-energy rays to kill cancer cells and keep them from growing. Radiation may also be used to reduce symptoms and improve your quality of life.

Yale Medicine offers expertise and highly individualized treatment for patients with small cell lung cancer. “We personalize the management approach for each patient,” says Dr. Park.

Explaining further, he says, “Our medical oncologists, radiation oncologists and surgeons communicate closely to determine a consensus recommendation regarding the overall treatment approach, but we also work with each patient to figure out a plan that makes the most sense for the individual. We follow up closely after the initial treatment, so that if the cancer returns, we are able to offer the most up-to-date options, including clinical trials, in a timely fashion.”