Between ten and twenty percent of all lung cancers are small cell lung cancers. They derive their name from the typical appearance of small, �oat�-like cancer cells under the microscope. This type of cancer is found almost exclusively in smokers or former smokers.

Small cell lung cancers typically arise in the airways near the center of the chest, and grow and spread rapidly. This rapid spread means small cell cancers are usually detected at an advanced stage. In addition to symptoms of lung cancer such as breathlessness, wheezing and chest pain, small cell cancers may produce hormones or hormone-like substances that result in conditions called paraneoplastic syndromes. These syndromes may result in dangerously low blood salt levels, blood clotting disturbances, and balance disturbances.

While people with untreated small cell cancers have a median survival time of only two to four months, once diagnosed these cancers are responsive to chemotherapy and radiation therapy. For patients with limited stage disease, where the cancer is limited to the side of the chest it originated in and some local lymph nodes, five-year survival rates are between ten to fifteen percent. Between 30 and 40 percent of all patients with small cell lung cancer fall into this group. For patients with extensive disease, treatment can extend survival from six months up to one year and five-year survival rates are between one and two percent. Factors linked to improved survival are being female and having good overall health status. Adverse prognostic factors are involvement of the liver or brain.

A number of clinical trials are underway to test various combinations of anti-cancer drugs to treat small cell lung cancer and radiotherapy to prevent spread of cancer cells. The National Cancer Institute website provides links to clinical trials by stage of disease, type of trial and geographic location.