Small Cell Lung Cancer

Small cell lung cancer (SCLC) accounts for about 15% of all lung cancers. In addition to existing treatment approaches, several promising new treatment approaches are being developed.

This website can help you:

  • Learn about small cell lung cancer
  • Understand the treatment options available for small cell lung cancer
  • Consider whether participating in a clinical trial might be right for you
  • Understand how to manage the side effects associated with lung cancer treatment

What is small cell lung cancer?

Small cell lung cancer is one of the major types of lung cancer. The other is non-small cell lung cancer. Small cell lung cancer cells look flat and smaller than normal, healthy cells. It is sometimes also called oat cell cancer.

Small cell lung cancer

Small cell lung cancer usually starts in the bronchi in the center of the chest, although about 5% of the time it is found in the periphery of the lungs. Small cell lung cancer is a type of neuroendocrine tumor.1

Small cell lung cancer accounts for about 15% of all lung cancers, and is found more often in people with a history of tobacco use. Sometimes, non-small cell lung cancer (NSCLC)—another type of lung cancer—may change into small cell lung cancer after treatment with drugs such as tyrosine kinase inhibitors.

Diagnosing small cell lung cancer

This type of lung cancer may be diagnosed in many different ways. In addition, doctors have come up with very specific modes of categorizing lung cancers to help treat them better. Understanding the ways that doctors categorize lung cancers may help you understand your diagnosis.

How is Small Cell Lung Cancer Diagnosed?

Many different tests are used to diagnose lung cancer and determine whether it has spread to other parts of the body. Some can also help to decide which treatments might work best. The steps and tests used in diagnosing small cell lung cancer include:

  • Imaging tests
  • Laboratory tests
  • Biopsies

Not all of these will be used for every person. The approaches used for an individual will depend on medical history and condition, symptoms, location of the nodule(s), and other test results.

Read the Diagnosing Lung Cancer section to learn about the different steps and tests for making a lung cancer diagnosis.

Stages of Lung Cancer

Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting other parts of the body. Doctors use diagnostics to determine the cancer’s stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to recommend a treatment plan.

Staging of small cell lung cancer is described in two different ways:

  • Traditionally, the terms “limited stage” and “extensive stage” have been used
    • Limited stage means the cancer is only in the lung
    • Extensive stage means the cancer has spread widely throughout a lung, to the other lung, to lymph nodes on the other side of the chest, or to distant organs. Many doctors also call cancer that has spread to the fluid around the lung "extensive stage."
  • More recently, the same system that is used for non-small cell lung cancer is being used for small cell lung cancer
    • A number from one through four (I, II, III, or IV), based on the TNM system

About 30% of people diagnosed with small cell lung cancer have limited-stage disease at the time of their diagnosis.2

The Lung Cancer Staging section provides more information about this way of understanding small cell lung cancer.

Biomarker Profile

Lung cancer describes many different types of cancer that start in the lung or related structures. There are two different ways of describing what kind of lung cancer a person has:

  • Histology—what the cells look like under a microscope. Small cell lung cancer is a histological type of lung cancer. Non-small cell lung cancer is another histological type.
  • Biomarker profile (also called molecular profile, genetic profile, or signature profile)—the genetic mutations, or characteristics, as well as any other unique biomarkers, found in a person’s cancer that allowed the cancer to grow.

A person’s lung cancer may or may not have one of the known mutations that drive small cell lung cancer. Known mutations in small cell lung cancer include TP53 and RB1. (Note that there are currently no approved treatments that target any of these small cell lung cancer mutations.)3,4

Treatment options for small cell lung cancer

There are a number of treatment options for small cell lung cancer. Which ones are used to treat a specific patient’s lung cancer will depend on the stage of the cancer and the patient’s overall health and preferences.

Treatment options fall into two categories:

  • Those that are available for your doctor to prescribe.
    • These have already been approved by the FDA in the U.S. or other drug regulatory agencies in other countries
  • Those that are being studied in clinical trials

What Are Currently Approved Treatment Options?

Approved treatment options for small cell lung cancer include:

  • Surgery
  • Radiation therapy
  • Chemotherapy

In addition, several new types of treatment are being studied for small cell lung cancer, including immunotherapy. These are available through clinical trials.

It is important to note that a patient’s age has never been useful in predicting whether that patient will benefit from treatment. Age should never be used as the only reason for deciding what treatment is best, especially for older patients who are otherwise physically fit and have no medical problems besides lung cancer.5

Read more about approved treatment options for small cell lung cancer by stage in the Treatment Options for Small Cell Lung Cancer by Stage section.

Surgery

While surgery is a treatment option, it is not commonly performed in small cell lung cancer patients. There is little evidence that surgery is effective except in those patients whose cancer is very limited.  When surgery is done, it is typically accompanied by adjuvant chemotherapy or a combination of chemotherapy and radiation therapy.2,6,7

Read more about different surgical options and what to expect after surgery in the Treatment Options: Surgery section.

Radiation Therapy

Radiation therapy is a type of cancer treatment that uses high-powered energy beams to kill cancer cells. Depending on the individual patient’s situation, radiation therapy may be used when trying to cure cancer, control cancer growth, or relieve symptoms caused by the tumor, such as pain.

The type of radiation therapy most often used for treating small cell lung cancer is external beam radiation therapy (EBRT).

Small cell lung cancer responds well to radiation therapy. This is usually given in combination with chemotherapy for limited-stage small cell lung cancer during the first months of chemotherapy treatment. Radiation to the brain among patients whose cancer has shrunk after treatment may also be used. In this case, use of radiation is recommended because it reduces the risk of the cancer spreading to the brain. Radiation therapy may also be used as a palliative treatment for extensive or recurrent disease.2,6,7

Read more about radiation therapy, including how it works, how and when it is given, the different kinds, and common side effects, in the Treatment Options:  Radiation Therapy section.

Chemotherapy

Chemotherapy is a systemic treatment that works by targeting and killing the rapidly growing cancer cells. It is the primary treatment for small cell lung cancer. Small cell lung cancer patients tend to have a good initial response to chemotherapy. The most common treatment for patients with both limited-stage and extensive-stage small cell lung cancer is a combination therapy. This includes a platinum-based drug, such as carboplatin or cisplatin, along with another chemotherapy drug, most often etoposide but also irinotecan.2,6,7

As mentioned earlier, radiation therapy is typically given together with chemotherapy for limited-stage small cell lung cancer. Combination chemotherapy may be used alone if a patient cannot tolerate radiation therapy.2

Read more about chemotherapy, including how it works, how and when it is given, and possible side effects and how to manage them, in the Treatment Options: Chemotherapy section.

What clinical research study (clinical trial) treatment options are available?

In addition to the approved treatments described above, doctors are testing several new types of treatment in clinical trials for people with small cell lung cancer.  The following describe some, but by no means all, of the clinical trials available for people with small cell lung cancer.

Targeted Therapy

Two types of targeted treatments are being tested in clinical trials for people with small cell lung cancer:

  • PARP inhibitors block a protein called PARP that small cell lung cancer uses to protect itself from chemotherapy. These drugs, including  veliparib and talazoparib, have shown promising results in combination with chemotherapy.
  • Notch inhibitors block the Notch pathway that is active in SCLC. Drugs such as RovaT that target this pathway are also being tested in clinical trials. Early results suggest that RovaT is effective in small cell lung cancer patients whose cancer produces a protein called DLL3.8,9

Immunotherapy

Three main types of immunotherapy are now being studied in clinical trials for people with all stages of small cell lung cancer:

  • Immune checkpoint inhibitors (anti-PD1, anti-CTLA-4, anti-PD-L1) by themselves or combined with other drugs such as chemotherapy. Nivolumab and pembrolizumab are two immune checkpoint inhibitors that are already approved for non-small cell lung cancer.8,9 A clinical trial with nivolumab and another checkpoint inhibitor, ipililumab, suggests that this combination may be effective in small cell lung cancer.
  • CAR-T cells: T-cells, a special type of immune cell, are removed from a patient’s body, taught to recognize the small cell lung cancer, and put back into the patient
  • Antibodies against a protein called Fuc-GM1 that is found in small cell lung cancer in high amounts

For more about immunotherapy, including how the immune system works, possible side effects, other kinds of immunotherapy being studied, and questions to ask your health care team, see the Treatment Options: Immunotherapy section.

New Approaches to Existing Treatments

In addition to new treatments, doctors are also trying new approaches to existing treatments. Some examples include8,9:

  • Radiation therapy given in combination with chemotherapy and surgery
  • Using imaging procedures, such as PET and CT scans, to help doctors guide radiation therapy so that higher doses can be delivered directly to the tumor, causing less damage to healthy tissue

Managing symptoms and side effects

As already noted, lung cancer treatments can cause side effects. Some cancer therapy side effects are temporary, while others can be more long-term. When you start a new treatment, you should discuss with your doctor which potential side effects to expect, what can be done to manage them, and which side effects are serious and need to be reported immediately. Often, drugs can be prescribed to help reduce many of these side effects.  

In addition to the side effects of lung cancer treatment, lung cancer itself can result in a number of symptoms. Read more about the symptoms of lung cancer.

Note: It’s important to let your doctor or nurse know if you are experiencing any problems while on treatment, so they can sort out whether the problems are related to treatment or not.

Tips for managing specific symptoms and side effects related to treatment can be found in the Support & Survivorship section of the website, along with other practical and supportive resources for patients/survivors and caregivers.

To help reduce the severity and duration of most side effects and alleviate the cancer’s symptoms, you may want to request palliative care, also called “supportive care” or “symptom management.” There is sometimes confusion about the difference between palliative care and hospice care. Hospice care is a form of palliative care given only to patients whose life expectancy is six months or less. On the other hand, palliative care in general is an extra layer of support than can be initiated alongside other standard medical care. In fact, scientific evidence is starting to emerge that shows that palliative care may actually help patients live longer.

Read more about how palliative care can improve quality of life from the time of diagnosis.

Your health care team

There are a number of doctors and other medical professionals who diagnose and treat people with lung cancer. Together, they make up the comprehensive medical or health care team that a patient sees over the course of his or her care. Your health care team can describe your treatment options, the expected results of each option, and the possible side effects. You and your health care team can work together to develop a treatment plan.

Read more about what each member of your health care team does.

Updated July 7, 2016.


Reference

  1. Wistuba I, Brambilla E, Noguchi M. Chapter 17: Classic Anatomic Pathology and Lung Cancer. In: Pass HI, Ball D, Scagliotti GV, eds. The IASLC Multidisciplinary Approach to Thoracic Oncology. Aurora, CO: IASLC Press; 2014:217-240.
  2. Small Cell Lung Cancer Treatment-Health Professional Version (PDQ®). National Cancer Institute website. http://www.cancer.gov/types/lung/hp/small-cell-lung-treatment-pdq#section/all.  Updated February 18, 2016. Accessed March 8, 2016.

  3. Molecular Profiling of Lung Cancer. My Cancer Genome website. https://www.mycancergenome.org/content/disease/lung-cancer/ . Updated January 26, 2016. Accessed March 7, 2016.

  4. Peifer, M, et al. Integrative genome analyses identify key somatic driver mutations of small-cell lung cancer. Nature Genetics, 2012. Vol 44: Number 10: 1104-1112. doi: 10.1038/ng.2396. http://pubman.mpdl.mpg.de/pubman/item/escidoc:1702986/component/escidoc:1711814/Peifer.pdf. Accessed March 8, 2016.

  5. Aging and Cancer. American Society of Clinical Oncology website. http://www.cancer.net/navigating-cancer-care/older-adults/aging-and-cancer. Approved August 2012. Accessed March 8, 2016.

  6. Rudin, et al. Treatment of Small-Cell Lung Cancer: American Society of Clinical Oncology Endorsement of the American College of Chest Physicians Guide. Journal of Clinical Oncology, 2015. Vol 33: Number 34: 4101-4106l. doi: 10.1200/JCO:205.63.7918. http://jco.ascopubs.org/content/33/34/4106. Accessed March 8, 2016.

  7. Lung Cancer – Small Cell: Treatment Options. American Society of Clinical Oncology website. http://www.cancer.net/cancer-types/lung-cancer-small-cell/treatment-options.  Updated August 20, 2015. Accessed March 8, 2016.

  8. ClinicalTrials.gov. U.S. National Institutes of Health website. http://clinicaltrials.gov. Accessed March 8, 2016.

  9. Bunn Jr PA, et al. Small Cell Lung Cancer: Can recent advances in biology and molecular biology be translated into improved outcomes? In-press. Journal of Thoracic Oncology, 2016. doi: 10.1016/j.jtho.2016.01.012.

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