Extensive-Stage Small Cell Lung Cancer

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When small cell lung cancer (SCLC) is in the extensive stage, it means that the cancer has spread to other parts of the body, such as the other lung or brain. The liver, adrenal glands, and bone are also common sites of metastasis. Unlike non-small cell lung cancer (NSCLC), which is divided into four main stages and several substages, extensive stage is one of only two stages of SCLC (the other being limited stage).

SCLC is less common than NSCLC, accounting for about 10% to 15% of all lung cancers. It tends to be more aggressive, growing rapidly and spreading quickly. Though extensive-stage small cell lung cancer cannot be cured and has a poor prognosis, it may respond to chemotherapy and newer treatments.

Symptoms of Extensive-Stage SCLC

In the early, limited-stage of SCLC, you may have no symptoms at all. As the cancer progresses, you might begin to have a persistent cough or recurrent lung infections. These problems will continue to become more severe as the cancer grows and spreads, and you will develop increasingly debilitating symptoms.

Symptoms of extensive-stage small cell lung cancer can be categorized by those that affect the lungs, those caused by paraneoplastic syndromes (abnormal immune responses 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-Eaton myasthenic syndrome)
  • Loss of coordination and difficulty speaking (paraneoplastic cerebellar degeneration)
  • Clubbing (rounding) of the fingernails
  • Weakness, fatigue, and a low sodium level in the blood (also known as the syndrome of inappropriate antidiuretic hormone secretion, or SIADH)

Symptoms related to metastasis include:

Causes

SCLC is initially caused by exposure to smoke or other toxins. In fact, approximately 95% of people diagnosed with SCLC are current or former smokers. Tobacco use is the biggest risk factor for contracting small cell lung cancer.

Researchers believe that the carcinogens in tobacco smoke damage DNA in proto-oncogenes, which regulate cell growth, and tumor suppressor genes, which are involved in repairing or eliminating damaged cells. These mutated cells then grow uncontrollably and unchecked, quickly developing into malignant tumors.

Prolonged exposure to secondhand smoke also increases the risk of lung cancer, as does exposure to other less common environmental agents including asbestos and radon.

SCLC will often go unnoticed in the early stages, allowing it progress beyond the limited stage and transition to extensive stage before it's found.

Diagnosis

Doctors base their diagnosis of small cell lung cancer on several specialized tests, including:

  • Physical exam and health history: In addition to assessing overall health, your doctor will ask about smoking history and possible job-related chemical exposure.
  • Laboratory tests: Samples of tissue, blood, urine, or other substances are examined and may be re-examined at a later time to check for changes.
  • Chest X-ray: Images of the organs and the bones in the chest will help determine if there are tumors and where they may be located.
  • Computed tomography (CT) scan: Scans of the entire chest will be taken to check for abnormal tissue. Scans may also be taken of the brain and abdomen to check common sites of lung metastases.
  • Sputum cytology: A sample of mucus from the lungs is examined under a microscope to check for cancer cells.
  • Biopsy: Tissue and fluid samples are taken from the lung and examined for cancer cells.
  • Bronchoscopy: A scope with a camera is inserted through the nose or mouth into the trachea and lungs to assess the lung tissue.
  • Thoracoscopy or mediastinoscopy: These are two types of surgical procedures in which camera scopes are inserted into the chest to view the area. A tissue sample may be taken for analysis as well.
  • Thoracentesis: Fluid is removed from the space between the lining of the chest and the lung to look for cancer cells.
  • Immunohistochemistry: Tissue samples are sent for lab analysis to check for certain antigens (markers) to help diagnose cancer and identify what type of cancer you have.

Roughly 60% to 70% of people with small cell lung cancer will have extensive disease at the time of diagnosis.

SCLC will be staged at the time of diagnosis. Doctors will identify the cancer as extensive stage SCLC if it meets any of the following criteria:

  • Cancer has spread widely throughout the initial lung.
  • Tumors have spread to the other lung or to lymph nodes on the opposite side of the chest.
  • Cancer has spread to other parts of the body.

Depending on your doctor, the disease may also be considered extensive if it has spread to the fluid around the lung.

Treatment

For previous generations, chemotherapy was the primary treatment for both limited and extensive stage SCLC. Sometimes it would be combined with radiation therapy. Today, a combination of chemotherapy and immunotherapy drugs is the preferred regimen for the more advanced stage of small cell lung cancer.

  • Chemotherapy involves orally or intravenously administrating cytotoxic medications that kill cancer cells.
  • Immunotherapy drugs are medications that boost your immune system so you can effectively fight cancer. When these treatments are combined, they have been shown to prolong survival.

For first-line treatment, the platinum chemo drug VePesid (etoposide) is combined with the immunotherapy drug Tecentriq (atezolizumab).

While these treatments can relieve symptoms and extend life, extensive small cell lung cancer is not curable. As it progresses, treatment options may switch from battling the cancer to easing symptoms. Radiation and chemotherapy may be used as palliative therapy at this point to help you manage pain or complications.

Prognosis

Survival rates for small cell lung cancer have improved since the addition of new treatment but still remain low.

Without treatment, the average life expectancy for a person with an extensive-stage small cell lung cancer 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 4%.

Treatment of other fast-growing cancers, such as leukemia, has come a long way, and it is hoped that better treatments for small cell lung cancer will be found in the near future. For now, patients need to prepare for the likelihood that extensive small cell lung cancer will not go into remission, and if it does, it's likely to recur within two years.

Coping

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 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.

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