Small-cell lung cancer (SCLC) makes up about 15% of lung cancers. It tends to be more aggressive than the other main category of lung cancer called non-small cell lung cancer and has a relative 5-year survival rate almost four times lower.

Doctors often divide SCLC into limited and extensive stages depending on how far it has progressed. Determining which stage you’re in helps them understand the best way to treat your cancer and predict your outlook.

Limited-stage SCLC is often treated with a combination of chemotherapy, radiation therapy, and surgery. Extensive-stage SCLC isn’t considered curable, and treatment usually revolves around managing your symptoms.

In this article, we take a deeper look at how doctors define limited-stage SCLC, how it’s treated, and what the outlook for people with it is.

Most doctors divide small-cell lung cancer into two stages: limited stage and extensive stage.

Roughly one in three people who receive a diagnosis of SCLC have limited-stage SCLC.

In limited-stage SCLC, the cancer is contained to one side of your chest. Although doctors might consider your cancer extensive if there are widespread tumors throughout your lung.

Some doctors still consider SCLC limited if the cancer has spread to the lymph nodes above your collar bone on the same side. Doctors will also sometimes consider the cancer limited when it spreads to lymph nodes in the middle of your chest even if they’re on the other side of your body.

Doctors diagnose extensive-stage SCLC when the cancer has spread to:

  • your other lung
  • the area between your lungs
  • lymph nodes on the other side of your body
  • distant tissues such as your brain or liver

The tumor, nodes, metastasis (TNM) staging system is also sometimes used to classify SCLC. This system classifies your cancer from stages 1 to 4 based on:

  • Tumor: how big and far your tumor has grown
  • Nodes: whether it’s spread to nearby lymph nodes
  • Metastasis: whether it’s spread to distant organs or tissues

In the early stages, SCLC might not cause any noticeable symptoms. Symptoms tend to get worse as the tumor grows and blocks your airways.

The most common initial symptoms are:

Other symptoms include:

Catching SCLC in the limited stage gives you the best chance of having a good outcome. For most people, their lung cancer isn’t found until it starts causing problems.

A doctor will start the diagnostic process by examining your medical history and performing a physical exam. If they suspect that you may have lung cancer or another lung problem, they may send you for imaging tests.

A chest X-ray is the most common initial imaging test ordered to look for lung abnormalities. Other imaging tests include:

The actual diagnosis of cancer is made by looking at cells from your lung under a microscope. A doctor may take a sample of your:

  • lung secretions (sputum cytology)
  • fluid around your lungs (thoracentesis)
  • an abnormal section of your lungs (needle biopsy)

Blood tests such as a complete blood count and blood chemistry test may be used to measure your overall health and to see if you’re healthy enough for surgery.

Limited-stage SCLC is often treated with more aggressive treatment than extensive-stage SCLC. Extensive-stage SCLC isn’t considered curable, so treatment usually focuses on improving your quality of life and lowering your symptoms.

According to the National Cancer Institute, treatment for limited-stage SCLC may include:

  • chemotherapy with multiple drugs and radiation therapy to your chest
  • chemotherapy with multiple drugs for people who can’t receive radiation therapy
  • surgery and then chemotherapy
  • surgery and then chemotherapy with radiation therapy
  • clinical trials investigating new types of chemotherapy drugs, surgery, and radiation therapy

Approximately 10% to 20% of people who received a diagnosis of SCLC have cancer that spreads to their brain. If your treatment is successful, a doctor may also recommend radiation therapy to your brain later to destroy any cancer cells that couldn’t be found.

Treatment for extensive SCLC may include:

  • immune checkpoint inhibitor therapy with multiple chemotherapy drugs
  • multiple chemotherapy drugs
  • radiation therapy to their chest in people who respond well to chemotherapy
  • radiation therapy to your brain or other areas where the cancer has spread to improve your symptoms
  • clinical trials of new treatments

The 5-year relative survival rate for SCLC is about 7%. The 5-year relative survival rate refers to the number of people still alive after 5 years with the cancer compared with the number of people still alive after 5 years in the general population.

The outlook for people with limited-stage SCLC is better than the outlook for people with extensive-stage SCLC. Only about 2% of people with extensive-stage SCLC are alive after 5 years. According to the Canadian Cancer Society, limited-stage SCLC has a median survival rate of 12 to 16 months with treatment.

These survival rates can give you an idea of what to expect, but many factors can influence how you respond to treatment. Factors linked to a better overall survival include:

  • early cancer stage
  • losing less than 10% of your body weight
  • having good daily function
  • being a person assigned female at birth
  • good overall health
  • certain genetic changes in cancer cells

A doctor can give you the best idea about what to expect.

Limited-stage SCLC is limited to one lung or possibly one lung and nearby lymph nodes.

The outlook for people with limited-stage SCLC is better than the outlook for people with extensive-stage SCLC, but less than half of people survive at least 5 years after receiving a diagnosis of limited-stage SCLC.

Researchers are continuing to explore new treatments for limited-stage SCLC and how to best treat it. A doctor can help you figure out which treatment is best for you.