Extensive Stage Small Cell Lung Cancer

Definition, Symptoms, Treatments, and Prognosis

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Small cell lung cancer is less common than non-small cell lung cancer, accounting for about 15 percent of lung cancers. It tends to be more aggressive, growing rapidly and spreading quickly, but often responds well to chemotherapy. Unlike non-small cell lung cancer, the malignancy is divided into only two stages: limited and extensive.

Extensive stage small cell lung cancer is defined as the stage during which the cancer has metastasized (spread) to other parts of the body, such as the lung or brain. The liver, adrenal glands, and bone are also common sites of metastasis.

Roughly 60 to 70 percent of people with small-cell lung cancer will have extensive disease at the time of diagnosis. In the past, chemotherapy was the primary treatment, with or without radiation. In 2018, however, it was found that using an immunotherapy drug in combination with chemotherapy could prolong survival.


Symptoms of extensive-stage small cell lung cancer can be categorized by those that affect the lungs, those caused by paraneoplastic syndromes (an abnormal immune response triggered by the tumor), and those related to metastasis.

Symptoms related to the lungs include:

Symptoms of paraneoplastic syndromes include:

  • Muscle weakness in the upper limbs, vision changes, and difficulty swallowing (Lambert-Eaten myasthenic syndrome)
  • Weakness, fatigue, and a low sodium level in the blood (also known as the syndrome of inappropriate antidiuretic hormone secretion, or SIADH)
  • Loss of coordination and difficulty speaking (paraneoplastic cerebellar degeneration)
  • Clubbing (rounding) of the fingernails

Symptoms related to metastasis include:


In the past, the treatment of extensive-stage small-cell lung cancer most commonly involved chemotherapy administered on its own. A 2018 study published in The New England of Journal of Medicine, however, found that first-line therapy (the initial treatment) using the immunotherapy drug Tecentriq (atezolizumab) in combination with the chemotherapy agents carboplatin and etoposide significantly prolonged survival relative to using chemotherapy alone. Due to these findings, the combination was given priority review by the FDA.

Sometimes radiation may be used as a form of palliative therapy to help relieve symptoms, such as bone pain, bleeding of the lungs, airway obstruction, or severe neurological complications.


Survival rates for small cell lung cancer have improved significantly since the addition of radiation therapy to treatment but still remain low.

Without treatment, the average life expectancy for a person with an extensive diagnosis is two to four months. With treatment, the expectancy rises to between six and 12 months, with a median five-year survival rate of up to 8 percent.

As we have come a long way in treating other fast-growing cancers, such as leukemia, it is hoped that better treatments will be found to treat small cell lung cancer in the near future.


Studies suggest that learning what you can about your lung cancer can improve your quality of life, and possibly even your outcome. Ask questions. Learn about clinical trials. Consider joining a support group.

Many of us hesitate to talk about end-of-life issues, but discussing these with your doctor and your family—even if all of you are hoping for a cure—is associated with fewer feelings of loneliness and a better quality of life.

Never lose hope, even if you have chosen not to pursue further treatment. Hope for quality time with loved ones, with good control of your symptoms. Hope for the future of your loved ones who will remain, with memories of you in their hearts.

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