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About Lung Cancer | Diagnosis | Types

Small Cell Lung Cancer

Small cell lung cancer (SCLC) is one of the most aggressive forms of lung cancer. Understanding what makes SCLC different, how it develops, how it’s diagnosed, and how it’s staged is the first step toward finding the best treatment and the best outcomes.

Explore SCLC Treatment Options

UNDERSTANDING SCLC

Small Cell Lung Cancer Treatment Advancements: Unlocking Hope Through Breakthrough Therapies

Dr. Sands and patient advocate Maida, emphasize the critical role of innovative therapies and clinical trials in transforming small cell lung cancer care, encouraging patients to explore all available options for the best outcomes.

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What is Small Cell Lung Cancer?

Small cell lung cancer is one of the two major types of lung cancer — the other being non-small cell lung cancer (NSCLC). SCLC is an uncontrolled growth of small cells in the lung and accounts for approximately 13% of all lung cancer diagnoses. It is also known as oat cell cancer because of the shape of the cancer cells when viewed under a microscope.

Unlike NSCLC, which may develop in several different cell types, SCLC originates from neuroendocrine cells, specialized cells in the lungs that produce hormones and respond to nerve signals. SCLC typically starts in the breathing tubes (bronchi) near the center of the chest.

What Makes SCLC Different from Non-Small Cell Lung Cancer?

SCLC behaves very differently from NSCLC in several important ways:

  • Faster growth rate: SCLC tumors can double in size in as little as 25 days, compared to months or years for many NSCLC tumors.
  • Earlier spread: By the time most people develop symptoms and seek medical care, SCLC has often already spread beyond the lungs to lymph nodes or other organs.
  • Strong initial treatment response: SCLC typically responds well to initial chemotherapy and radiation, but the disease often returns within 6–8 months and can become more resistant to further treatment.
  • Different staging system: In addition to the standard four-stage system used for NSCLC, a 2-stage system (limited stage and extensive stage) can also be used for SCLC.
  • Strong link to smoking: While anyone with lungs can get lung cancer, SCLC has a particularly strong association with tobacco use. It is rare in people who have never smoked.

What Causes Small Cell Lung Cancer?

The primary risk factor for SCLC is tobacco exposure. Approximately 95% of people diagnosed with SCLC are current or former smokers. However, it is important to understand that a lung cancer diagnosis is never the patient’s fault and every patient deserves the best possible care regardless of smoking history.

Other risk factors include:

  • Secondhand smoke exposure
  • Radon gas exposure: A colorless, odorless radioactive gas that can accumulate in homes and buildings
  • Occupational hazards: Exposure to asbestos, arsenic, nickel, chromium, or other toxic chemicals
  • Radiation exposure: Previous radiation therapy to the chest
  • Family history: Having close relatives with lung cancer
  • Military service: Veterans face a 25% higher risk of lung cancer due to environmental and occupational exposures during service.

Signs and Symptoms of Small Cell Lung Cancer

SCLC often grows and spreads before causing noticeable symptoms, which is one reason it is frequently diagnosed at an advanced stage. When symptoms do appear, they may include:

  • A persistent cough that worsens over time
  • Coughing up blood (hemoptysis)
  • Shortness of breath
  • Chest pain that worsens with deep breathing, coughing, or laughing
  • Hoarseness or voice changes
  • Unexplained weight loss and loss of appetite
  • Fatigue and weakness
  • Recurring respiratory infections such as bronchitis or pneumonia
  • Swelling in the face, neck, arms, or upper chest (caused by a tumor pressing on the superior vena cava)

Because SCLC can produce hormones and other substances, some patients may experience paraneoplastic syndromes — conditions caused by the cancer’s effect on distant organs. These can include muscle weakness, nausea, fluid retention, or elevated blood calcium levels. If you are experiencing any of these symptoms, talk to your doctor promptly.

How Is Small Cell Lung Cancer Diagnosed?

Diagnosing SCLC typically involves several steps:

  • Imaging: A CT scan of the chest and abdomen to determine the size and location of the tumor and whether it has spread.
  • Biopsy: A tissue sample is taken from the tumor — either through a bronchoscopy, needle biopsy, or surgical procedure — and examined under a microscope to confirm the cancer type.
  • Additional staging tests: PET scans, brain MRI, and bone scans may be used to determine whether the cancer has spread to other parts of the body.
  • Blood tests: Complete blood counts and chemistry panels help assess overall health and organ function before treatment begins.

Important: If you have been diagnosed with lung cancer, ask your oncologist about comprehensive biomarker testing. While SCLC does not currently have the same range of targetable mutations as NSCLC, biomarker information can help identify clinical trial opportunities and guide treatment decisions.

SCLC Staging: Limited vs. Extensive

In addition to the Stage 1-4 staging system used for other cancers, SCLC is also classified into two broad stages – limited stage and extensive stage:

Limited-Stage SCLC

Cancer is found in one lung and may have spread to nearby lymph nodes on the same side of the chest. The cancer is contained within an area that can be treated with a single radiation field. Approximately 1 in 3 patients are diagnosed at limited stage.

Extensive-Stage SCLC

Cancer has spread beyond one lung to the other lung, to distant lymph nodes, or to other organs such as the liver, bones, brain, or adrenal glands. Approximately 2 in 3 patients are diagnosed at extensive stage.

The stage at diagnosis is one of the most important factors in determining treatment options and prognosis. This is why early detection can make a significant difference in outcomes.

Can Small Cell Lung Cancer Be Detected Early?

Early detection of SCLC is difficult because the disease grows and spreads so quickly. However, low-dose CT (LDCT) screening is recommended for people at high risk of lung cancer and can sometimes detect lung cancer before symptoms develop.

You may be eligible for LDCT screening if you:

  • Are between 50 and 80 years old
  • Have a 20 pack-year smoking history (for example, 1 pack per day for 20 years)
  • Currently smoke or have quit within the past 15 years

When lung cancer is detected at its earliest stage before it spreads, the 5-year survival rate increases substantially when SCLC is detected early. Talk to your doctor about whether screening is right for you.

Can Small Cell Lung Cancer Be Detected Early?

Early detection of SCLC is difficult because the disease grows and spreads so quickly. However, low-dose CT (LDCT) screening is recommended for people at high risk of lung cancer and can sometimes detect lung cancer before symptoms develop.

You may be eligible for LDCT screening if you:

  • Are between 50 and 80 years old
  • Have a 20 pack-year smoking history (for example, 1 pack per day for 20 years)
  • Currently smoke or have quit within the past 15 years

When lung cancer is detected at its earliest stage before it spreads, the 5-year survival rate increases substantially when SCLC is detected early. Talk to your doctor about whether screening is right for you.

Screening is No Small Matter

The earlier lung cancer is detected, the more treatment options are available to you. Hear from Dusty and Maida about the importance of getting screened.

There Is Hope for SCLC Patients

While SCLC remains a challenging disease, the landscape is changing. After decades with few new treatment options, recent years have brought meaningful breakthroughs including:

  • new immunotherapy combinations
  • bispecific T-cell engagers
  • innovative clinical trials specifically designed for SCLC patients

LCFA is committed to funding the research that will transform outcomes for people living with small cell lung cancer. Every patient deserves access to the latest science, the best care team, and real hope.

FDA-Approved Treatments for Small Cell Lung Cancer

Types

  • Lurbinectedin (Zepzelca) + Atezolizumab (Tecentriq)

    Extensive-stage small cell lung cancer. It is used as maintenance treatment in adults whose disease has not progressed after first-line induction therapy with atezolizumab (or atezolizumab and hyaluronidase), carboplatin, and etoposide. The atezolizumab component works by blocking PD-L1, helping the immune system recognize and attack cancer cells.

     

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 10/02/2025

    Used in: Combination Therapy, Immunotherapy, SCLC

  • Durvalumab (Imfinzi) – Limited-Stage SCLC

    Limited-stage small cell lung cancer. It is used in adults whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy. Durvalumab works by blocking PD-L1, a protein that helps cancer cells hide from the immune system, allowing immune cells to recognize and attack the tumor. This was the first FDA-approved immunotherapy regimen for limited-stage SCLC.

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 12/04/2024

    Used in: Immunotherapy, SCLC

  • Durvalumab (Imfinzi) — Extensive-Stage SCLC

    Extensive-stage small cell lung cancer. It is used in combination with etoposide and either carboplatin or cisplatin as first-line treatment for adults with extensive-stage SCLC. Durvalumab works by blocking PD-L1, a protein that helps cancer cells hide from the immune system, allowing immune cells to recognize and attack the tumor.

     

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 03/27/2020

    Used in: Combination Therapy, SCLC

  • Atezolizumab (Tecentriq)

    Extensive-stage small cell lung cancer. It is used in combination with carboplatin and etoposide as first-line treatment for adults with extensive-stage SCLC. Atezolizumab works by blocking PD-L1, a protein that helps cancer cells hide from the immune system, allowing immune cells to recognize and attack the tumor.

     

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 03/18/2019

    Used in: Combination Therapy, Immunotherapy, SCLC

  • Tarlatamab-dlle (Imdelltra)

    Tarlatamab is given to small cell lung cancer patients who have already tried chemotherapy but whose cancer has come back or spread.

    This injectable medicine is an antibody that targets a protein on cancer cells called DLL3. By attaching to DLL3, tarlatamab helps the body’s immune system find and destroy the cancer cells. In a clinical trial, some patients who received tarlatamab had their tumors shrink or disappear for some time.

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 05/16/2024

    Used in: SCLC

  • Lurbinectedin (Zepzelca)

    Small cell lung cancer that is metastatic. It is used in adults whose disease has gotten worse during or after treatment with platinum chemotherapy. *This use is approved under FDA’s Accelerated Approval Program. As a condition of approval, a confirmatory trial(s) must show that lurbinectedin provides a clinical benefit in these patients.*

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 06/15/2020

    Used in: SCLC

  • Pembrolizumab (Keytruda)

    Small cell lung cancer that has metastasized. It is used in patients whose disease got worse during or after treatment with platinum chemotherapy and at least one other therapy.

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 03/01/2020

    Used in: Immunotherapy

  • Etoposide

    Etoposide is a chemotherapy drug primarily used to treat small cell lung cancer (SCLC) and sometimes applied in non-small cell lung cancer (NSCLC) cases. It works by targeting the enzyme topoisomerase II, which is essential for cancer cell division and growth. By disrupting this enzyme, etoposide causes DNA breaks in cancer cells, ultimately leading to their death. With a long-standing track record in lung cancer treatment, etoposide is recognized for its effectiveness.

    Approved for: NSCLC, SCLC

    Biomarkers: SCLC

    FDA Approval Date: 01/01/1983

    Used in: Chemotherapy

  • Carboplatin (Paraplatin)

    Carboplatin, also known as Paraplatin, is a chemotherapy drug used in the treatment of lung cancer, effective against both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). It disrupts the DNA replication in cancer cells, leading to their death. It can be employed as part of combination chemotherapy to enhance effectiveness, used after surgery to eliminate residual cancer cells, or given before surgery to shrink tumors for improved surgical outcomes. Additionally, carboplatin plays a role in palliative care for advanced lung cancer. First approved by the FDA in 1989, it has a proven track record in clinical practice over the past three decades.

    Approved for: NSCLC, SCLC

    Biomarkers: SCLC

    FDA Approval Date: 01/01/1989

    Used in: Adjuvant Therapy, Combination Therapy, SCLC

  • Topotecan Hydrochloride (Hycamtin)

    Topotecan hydrochloride, marketed as Hycamtin, is a chemotherapy drug primarily used in the treatment of small cell lung cancer (SCLC). The FDA first approved topotecan in 1996 for the treatment of patients with SCLC after disease progression following initial chemotherapy. It works as a topoisomerase I inhibitor, interfering with DNA replication in cancer cells. Topotecan is typically used in the second-line setting for SCLC patients whose disease has recurred or progressed after first-line treatment. It can also be considered in combination with other agents in certain cases.

    Approved for: SCLC

    Biomarkers: SCLC

    FDA Approval Date: 01/01/1996

    Used in: SCLC