Small Cell Lung Cancer


What is small cell lung cancer?

Small cell lung cancer is fast-growing lung cancer that develops in the tissues of the lungs. By the time a person gets a diagnosis, small cell lung cancer has typically spread (metastasized) outside of the lungs. This cancer is also more likely than other types of lung cancer to come back after treatment. Small cell lung cancer is sometimes, but not often, called oat cell cancer because the small, oval-shaped cells look like oat grains under a microscope.

What are the types of lung cancer?

Small cell lung cancer is the least common type of lung cancer. More people who have lung cancer — an estimated eight out of 10 — develop non-small cell lung cancer (NSCLC). Compared to NSCLC, small cell lung cancer grows faster and is more likely to spread.

What are the types of small cell lung cancer?

There are two types of small cell lung cancer. Cancer cells grow and spread differently depending on the type. Doctors named the types for the kinds of cells in the cancer and how they look under a microscope:

  • Small cell carcinoma.
  • Combined small cell carcinoma.

How common is small cell lung cancer?

An estimated 15% of people diagnosed with lung cancer have small cell lung cancer.

Who might have small cell lung cancer?

Smokers, people with a history of smoking and nonsmokers are all at risk for lung cancer. However, small cell lung cancer almost always develops in people who have a long history of tobacco use.

Symptoms and Causes

What causes small cell lung cancer?

While anyone can get lung cancer, current and former smokers are most at risk for small cell lung cancer. Other risk factors include:

  • Secondhand smoke.
  • Radiation exposure via cancer treatments, home radon or diagnostic imaging scans.
  • Family history of lung cancer.
  • Human immunodeficiency virus (HIV).
  • Workplace exposure to asbestos, arsenic, nickel, tar or other chemicals.
  • Air pollution.
  • Advanced age.

What are the symptoms of small cell lung cancer?

Early-stage small cell lung cancer that hasn’t spread rarely causes symptoms. As the disease progresses, you may experience:

Diagnosis and Tests

How is small cell lung cancer diagnosed?

Chest X-rays are typically the first step to screen for any type of lung cancer. If images show suspicious spots on a lung, your healthcare provider may order one or more of these diagnostic tests:

  • Imaging scans: Computed tomography (CT) and positron emission tomography (PET) scans detect lung tumors. These tests also can help gauge cancer spread. CT scans are the primary way to diagnose lung cancer.
  • Sputum cytology: This test checks for cancer cells in sputum, mucus coughed up from the lungs.
  • Biopsy: A needle biopsy removes tissue samples from the lungs. Lab pathologists check the biopsy for cancer cells.
  • Bronchoscopy: Using a bronchoscope, your provider looks inside the lung’s airways for tumors. At the same time, providers can remove tissue samples to biopsy.

What are the stages of small cell lung cancer?

Healthcare providers use a two-stage system to diagnose the spread of small cell lung cancer. This information also helps guide treatment. The two stages of small cell lung cancer are:

  • Limited: Cancer is confined to one lung and nearby lymph nodes. (Lymph nodes are part of the lymphatic system that help filter out diseased cells.)
  • Extensive: Cancer has spread to the other lung and lymph nodes. It also may have spread to bones, the brain and other organs.

Management and Treatment

What are the complications of small cell lung cancer?

Metastasis, or cancer spread, is a top concern for people who have small cell lung cancer. Small cell lung cancer can grow quickly and affect the brain, bones and liver and adrenal glands . Small cell lung cancer that spreads is treatable but generally isn’t curable. Other complications include:

  • Pleural effusion (fluid buildup in the area outside of the lungs).
  • Cancer recurrence (return) after treatment, often in the central nervous system (brain or spine) or chest.
  • Pain.
  • Shortness of breath.

How is small cell lung cancer managed or treated?

Treatment depends on many factors including your age, overall health and cancer stage. Treatment options include:

  • Radiation therapy: External radiation therapy uses a machine to deliver strong X-ray beams directly to the tumor. In addition to killing cancer cells, this therapy can relieve symptoms.
  • Chemotherapy: Your provider may combine chemotherapy drugs with other treatments to kill lingering cancer cells.
  • Immunotherapy: This treatment engages your body’s immune system to fight and destroy cancer cells. Immune checkpoint inhibitors are a type of immunotherapy that treats advanced small cell lung cancer.
  • Surgery: About one in 20 people with small cell lung cancer have a localized form that hasn’t spread outside of the lung. For this select group, surgery can remove part or all of the diseased lung. Once cancer spreads, surgery is no longer an option.


How can I prevent small cell lung cancer?

Because tobacco use is the top cause of small cell lung cancer, not smoking is the best way to protect your health. When you quit smoking — regardless of your age or years of tobacco use — your lungs start to heal, and cancer risk diminishes. These steps may also help:

  • Eat a nutritious diet.
  • Exercise regularly.
  • Maintain a healthy weight.
  • Test your home for radon, a natural, odorless, radioactive gas.
  • Install a mitigation system to remove radon from your home, if needed.
  • Protect yourself from cancer-causing chemicals (arsenic, asbestos, nickel) at work.

How can I detect small cell lung cancer sooner?

Regular low-dose CT scans can help detect lung cancer early, before it has a chance to spread. Radiation exposure, including during screening tests, is a concern if you’re at high risk for lung cancer. Low-dose CT scanners use about five times less radiation than traditional CT scanners. The Centers for Disease Control and Prevention recommends yearly lung cancer screenings using low-dose CT scans for those who meet all of these criteria:

  • Heavy smoker (defined as 30 pack years, or the equivalent of one pack per day for 30 years, two packs per day for 15 years, or three packs per day for 10 years).
  • Current or former smoker (last used tobacco within the past 15 years).
  • Between the ages of 55 and 70.

Outlook / Prognosis

What is the prognosis (outlook) for people who have small cell lung cancer?

Lung cancer claims the lives of more Americans every year than any other cancer. Symptoms often don’t appear until the cancer spreads. Once small cell lung cancer advances, it’s treatable but not curable. Detecting the cancer early through regular cancer screenings offers the best chance for improved survival. The overall five-year survival rate for people with limited-stage small cell lung cancer is about 20%. That number drops to 3% for extensive-stage small cell lung cancer.

Living With

When should I call the doctor?

You should call your healthcare provider if you have small cell lung cancer and experience:

  • Difficulty breathing.
  • Chest pain.
  • Bone pain.
  • Seizures.

What questions should I ask my doctor?

If you have small cell lung cancer, you may want to ask your healthcare provider:

  • Why did I get small cell lung cancer?
  • What stage is the lung cancer? What does this mean for my prognosis?'
  • What is the best treatment for the small cell lung cancer I have?
  • What are the treatment risks and side effects?
  • What type of follow-up care do I need after treatment?
  • How can I stop smoking?
  • Should I look out for signs of complications?

A note from Cleveland Clinic

Early cancer screenings and treatment advancements are helping people with small cell lung cancer live longer. If you’re at high risk for small cell lung cancer due to a history of smoking, talk to your healthcare provider about getting annual lung cancer screenings. These screenings can catch cancer early, when it’s most treatable. It’s never too late to gain health benefits when you stop smoking — even if you already have lung cancer. Your provider can help you quit.

Last reviewed by a Cleveland Clinic medical professional on 10/12/2020.


  • American Cancer Society. If You Have Small Cell Lung Cancer. ( Accessed 10/15/2020.
  • American Lung Association. Lung Cancer Basics. ( Accessed 10/15/2020.
  • Centers for Disease Control and Prevention. Basic Information About Lung Cancer. ( Accessed 10/15/2020.
  • Lung Cancer Foundation of America. Small Cell Lung Cancer. ( Accessed 10/15/2020.
  • National Cancer Institute. Small Cell Lung Cancer. ( Accessed 10/15/2020.
  • About HIV. ( Accessed 10/15/2020.

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