Extensive Stage Small Cell Lung Cancer

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Small cell lung cancer (SCLC) is less common than non-small cell lung cancer, accounting for about 10% to 15% of all lung cancers. It tends to be more aggressive, growing rapidly and spreading quickly, but it may respond to chemotherapy and newer treatments. Unlike non-small cell lung cancer, which is divided into four main stages and several substages, SCLC malignancies are divided into only two stages: limited and extensive.

Extensive-stage small cell lung cancer is defined as the stage during which lung cancer has metastasized (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.

Symptoms

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-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

Approximately 95% of people who are 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.

Diagnosis

Doctors base their diagnosis of small cell lung cancer upon 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.
  • CT scan (computed tomography scan): Scans will be taken of the entire chest 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 as well for analysis.
  • 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.

Treatment

For previous generations, chemotherapy was the primary treatment for SCLC. Sometimes it would be combined with radiation therapy. Today, a combination of chemotherapy and immunotherapy drugs are the preferred treatment for small cell lung cancer. Chemotherapy involves orally or intravenously administrating cytotoxic (cell-killing) 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 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%.

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. 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 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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