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Elderly woman with small cell lung cancer standing in the kitchen, cutting vegetables in preparation for a meal

What is small cell lung cancer?

Small cell lung cancer (SCLC) is one of the two main types of lung cancer. SCLC starts in the hormone-producing cells in the lungs and often grows quickly. SCLC is less common. It makes up only 10-15% of all lung cancer cases.

As small cell lung cancer can spread quickly to other areas of the body, many cases of this type of lung cancer aren’t found until its later stages. However, treatment options are available for all types and stages of small cell lung cancer.

From tailored chemotherapy to innovative clinical trials to cancer support, our hospitals provide a multidisciplinary approach to care for small cell lung cancer. You’ll have access to the resources and expertise to plan your next steps and confidently move forward.

Types of small cell lung cancer

Understanding your type of lung cancer helps you make informed choices about your care. Your care team will describe your small cell lung cancer as one of two types:

  • Small cell carcinoma

    This is the most common type of small cell lung cancer. It’s also called oat cell cancer because it looks similar to oats when viewed under a microscope.

  • Combined small cell carcinoma

    This type of lung cancer is a combination of both non-small cell cancer and small cell cancer. It’s rare—only accounting for 2-5% of cases of small cell lung cancer.

Small cell lung cancer vs. non-small cell lung cancer

Small cell lung cancer and non-small cell lung cancer are named for how the cancer cells look under a microscope. As the name suggests, small cell lung cancer cells look small and round.

The most important differences are how fast these types of lung cancer spread and their treatment options. SCLC is more aggressive and more likely to return after your initial treatment.

Small cell lung cancer symptoms

Small cell lung cancer may not cause any symptoms at first. In the early stages, SCLC is usually only found during an imaging test for another health concern. As the symptoms are often the same as other less serious lung conditions, many people don’t notice symptoms until this type of cancer has already started to spread.

Routine lung cancer screening is vital for catching the condition early. If you have a high risk of lung cancer based on your age and smoking history, screening could help detect SCLC before you ever have symptoms.

Older man with small cell lung cancer pushing a kayak off from the shore, while his wife, seated inside and holding a paddle, smiling

What causes small cell lung cancer?

The precise cause of small cell lung cancer is not fully understood. However, it is believed to develop when neuroendocrine cells of the lung grow uncontrollably. We do know the risk factors for small cell lung cancer. For example, most cases of SCLC are related to smoking.

SCLC risk factors

The biggest risk factor for small cell lung cancer is a history of smoking. The longer and heavier your smoking history, the greater the risk. Exposure to secondhand smoke also raises your risk. The American Lung Association says that secondhand smoke could increase your SCLC risk by nearly 30%. 

While rare, it is possible to get small cell lung cancer even if you haven’t smoked or been exposed to secondhand smoke.

Other risk factors include:

  • Exposure to harmful substances or chemicals, like asbestos, arsenic or soot
  • Exposure to radiation, including from radiation therapy to treat other cancers or exposure to radon gas
  • Exposure to high levels of air pollution
  • A family history of any lung cancer
  • Taking beta carotene supplements as a smoker
  • Having human immunodeficiency virus (HIV)

Diagnosing SCLC

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If you develop small cell lung cancer symptoms, your care team will use imaging and other diagnostic tests to get to the cause. These tests also help you understand your specific type of cancer, its location and where it has spread.

Lung cancer screening with a low-dose CT scan can catch SCLC before you ever have symptoms. Screening is recommended annually in people ages 50-80 with a smoking history of at least one pack of cigarettes per day for 20+ years.

Physical exam and medical history

Diagnosing small cell lung cancer starts with a visit to your doctor. Your provider will ask you questions about how you’re feeling and your medical and family history. You’ll also have an exam to help guide your next steps for testing.

Imaging tests

When you’re experiencing symptoms of small cell lung cancer or something is found on a screening, your treatment plan may begin with imaging tests. Your care team has a few options to look for lung cancer or determine if your cancer has spread to other areas of the body.

  • Chest X-ray: Chest X-rays aren’t used to screen for lung cancer, but you may have this imaging test to check lung symptoms. It can show signs of cancer or tumors in the lungs.
  • Computed tomography (CT) scan: A CT scan is used for lung cancer screening and to create detailed images of your cancer. It takes multiple X-ray images from different angles, providing information about the size and location of a tumor.
  • Magnetic resonance imaging (MRI) scan: MRI imaging provides your team with detailed images of soft tissues in your body to look at places where cancer may have spread. For example, in SCLC, it’s common to have an MRI of the brain.
  • Positron emission tomography (PET) scan: Using a small amount of radioactive sugar, a PET scan highlights areas of cancer cells throughout the body to look for cancer outside the lungs.
  • Bone scan: This test uses an injection of radioactive tracer to see if cancer has spread to your bones.

Sputum cytology

Cancer cells can be found in the sputum you cough up from your lungs. Sputum cytology takes samples of your sputum and looks for cancer cells in the lab. It’s usually performed with other tests, not as a stand-alone diagnostic test. The absence of cancer cells in sputum cytology does not rule out cancer.

Thoracentesis

Thoracentesis takes a sample of the fluid in the space around your lungs in your chest—if there is fluid accumulation. This procedure uses a needle carefully inserted into the chest to remove fluid, which is then sent to the lab to look for signs of cancer.

Biopsy

A lung biopsy gives your care team details about your type of lung cancer by taking a sample of the abnormal tissue from your lungs or lymph nodes. There are a few options for lung biopsy, and all of the samples are reviewed in the lab by a pathologist.

  • Transthoracic needle biopsy: With the help of imaging, an interventional radiologist guides a small needle into the chest to take a sample of lung tissue. For SCLC, a larger sample of tissue may be needed.
  • Bronchoscopy: Bronchoscopy uses a thin scope with a light guided down your throat into the airways. Your pulmonologist then takes samples of lung tissue using small tools like needles, forceps, brushes, or cryoprobes. Some of our hospitals offer robotic bronchoscopy, which provides advanced reach and precision, resulting in higher diagnostic yield.
  • Thoracoscopy: Thoracoscopy is a minimally invasive surgical procedure that reaches the lungs through a small incision. Special instruments and a small camera allow your surgeon to view the inside of the chest and take a biopsy.
  • Endobronchial ultrasound (EBUS): EBUS combines bronchoscopy with ultrasound imaging. It’s often used as the first diagnostic tool or to confirm a recurrence with a biopsy of any abnormal lung tissue along the airways.
  • Endoscopic esophageal ultrasound: This procedure uses ultrasound and endoscopy (a thin, flexible tube with a camera inserted down your throat) to view and biopsy any suspicious mass along the upper digestive tract. Your interventional pulmonologist can perform this as a combined endobronchial-endoscopic ultrasound procedure or as a stand-alone procedure by your gastroenterologist.
  • Mediastinoscopy or mediastinotomy: These procedures allow your chest surgeon to take samples of the lymph nodes under your breastbone. Mediastinoscopy is performed through a small incision using a scope. Mediastinotomy uses a large incision between your ribs.
Medical provider sitting at a desk with a patient, explaining an imaging picture showing the presence of small cell lung cancer.

Small cell lung cancer stages

Lung cancer stages provide more information about the size and location of your small cell lung cancer and if it has spread. Unlike non-small cell lung cancer and many other types of cancer, doctors don’t typically use five stages for small cell lung cancer. Most of the time, your SCLC stage will be placed into one of two stages: Limited-stage small cell lung cancer or extensive-stage small cell lung cancer.

  • Limited-stage small cell lung cancer

    Limited-stage small cell lung cancer is the earlier stage of the condition. Your SCLC is still limited to one side of the chest at this stage. You typically have more treatment options with limited-stage small cell lung cancer, but only about a third of cases are found this early.

  • Extensive-stage small cell lung cancer

    Extensive-stage small cell lung cancer is advanced cancer. At this stage, SCLC has spread to other areas of the body away from the original location in the lung, including the other side of the chest, brain or bones. Most cases of SCLC are at this stage when they are first diagnosed.

Small cell lung cancer treatment

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Your care team has several options to care for your small cell lung cancer and new lung cancer treatments are being studied daily to improve the options for SCLC. While non-small cell lung cancer is often treated with surgery, it is less common with small cell lung cancer. The most common treatments for SCLC are chemotherapy and radiation therapy.

Whether you have limited-stage small cell lung cancer or extensive-stage, our specialized lung cancer treatment programs bring together teams of specialists to create a comprehensive care plan that works for you.

Surgery

Surgery may be an option if your SCLC is found when it’s still small and limited to one side of the chest. However, this isn’t a standard treatment.

During surgery for small cell lung cancer, your surgeon removes areas of the lung where your cancer is located and nearby lymph nodes. The majority of people who have surgery for small cell lung cancer also undergo other treatments like chemotherapy or radiation.

Chemotherapy

Chemotherapy is one of the main treatments for small cell lung cancer. If you have limited-stage SCLC, chemotherapy is often used together with radiation therapy. For extensive-stage SCLC, you may have chemotherapy by itself or together with immunotherapy.

Your care team will have several options to customize chemotherapy to your needs, including different drug combinations and treatment schedules. Typically, you can expect to have four to six cycles of chemotherapy treatment for SCLC.

Immunotherapy

Immunotherapy is common in extensive-stage small cell lung cancer. This therapy helps your body’s immune system recognize cancer cells and slow their spread.

The primary immunotherapy drugs for SCLC are called checkpoint inhibitors. Your immune system uses specific proteins (checkpoints) that prevent your body from attacking your healthy cells. Checkpoint inhibitors block this particular function in cancer cells, so the body recognizes and attacks them.

Radiation therapy

Radiation therapy is often combined with chemotherapy to treat small cell lung cancer. Because SCLC is known to spread to the brain, it’s an option to have radiation therapy in the brain as a preventive measure as well.

Small cell lung cancer is often treated with external beam radiation, which targets specific areas of cancer with high-intensity rays from outside the body. There are several types of radiation therapy, including specialized computer-guided therapies that precisely target cancer and limit the effects on healthy tissue.

Frequently asked questions

  • Is small cell lung cancer curable?

    It’s rare for small cell lung cancer to be found when it’s curable. However, you have treatment options that may prolong your life and manage symptoms when living with small cell lung cancer.

  • How fast does small cell lung cancer spread?

    Small cell lung cancer usually spreads quickly when compared to other types. It’s considered an aggressive form of cancer, and about 2 in 3 cases aren’t found until the cancer has already spread to distant organs. SCLC may double in size over the course of just a few months.

  • Is small cell lung cancer hereditary?

    Not usually. While a few genes have been identified as playing a role in lung cancer, most small cell lung cancer cases are not caused by inherited genetic changes. The leading cause of small cell lung cancer is smoking.

  • Is small cell lung cancer terminal?

    It depends on the stage. When found early, the five-year survival rate for small cell lung cancer is about 30%. However, many people are diagnosed after it has spread. Even in extensive-stage cancer, you might have options to prolong your life.

  • Where does small cell lung cancer spread first?

    It’s common for small cell lung cancer to first spread to the lymph nodes in the middle of the chest. Cancer cells may continue spreading to distant areas of the body, including the adrenal glands, brain, bones or liver.

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