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According to the National Cancer Institute, small cell lung cancer (SCLC) accounts for approximately 13 percent of all diagnosed cases of lung cancer. Exposure to asbestos is a well-established cause of small cell lung cancer. In addition, it is well-known in the medical community that smoking and asbestos exposure results in a synergistic affect, which greatly increases a person's risk of developing lung cancer. One scientific study analyzed eight different studies on the subject and found that of the asbestos-induced lung cancers, small cell accounted for 28 percent of diagnosed cases.

Though the cells of SCLC are smaller than non-small cell lung cancer (NSCLC), they multiply quickly and can form large tumors that can spread to other regions of the body. When viewed under a microscope, the cells appear small and oval-shaped. Though other risk factors can come into play, smoking cigarettes is almost always the root cause of SCLC, as it is extremely rare for a person who never smoked to develop SCLC.

Also known as oat cell carcinoma and small cell undifferentiated carcinoma, SCLC commonly begins in the bronchi near the center of the chest. Unfortunately, SCLC is likely to spread widely throughout the body in early stages of development. Because of this factor, surgery is rarely an option for those affected by SCLC.

Symptomatic Differences Between SCLC and NSCLC

Various symptoms are commonly associated with lung cancer in an overall sense, but certain types of lung cancer can cause a group of specific symptoms. These are often referred to as "syndromes." Horner syndrome, for example, can occur with both small cell and non-small cell lung cancers and is associated with cancers that affect the upper part of the lungs. There are some syndromes, however, that are more commonly associated with SCLC.

Certain lung cancers produce hormone-like or other substances that can cause a variety of health problems, which are known as paraneoplastic syndromes. Some paraneoplastic syndromes are more commonly associated with SCLC, and these include:

• Syndrome of Inappropriate Antidiuretic Hormone (SIADH): This syndrome occurs when the cancer produces the hormone ADH, which causes the kidneys to retain water. Salt levels in the blood are consequently reduced and symptoms may include restlessness, confusion, loss of appetite, fatigue, nausea, vomiting, or muscle weakness or cramps. Gone untreated, serious cases can cause seizures and coma.
• Ectopic Cushing Syndrome: In this condition, cancer cells produce ACTH, a hormone that causes the adrenal gland to release cortisol. Excessive production of cortisol can lead to high blood pressure, weight gain, and weakness.
• Neurologic Problems: In some cases, SCLC can lead to nervous system complications. The Lambert-Eaton syndrome is a muscle disorder that causes the muscles around the hip to become weak, and in further development, muscles around the shoulders can become affected as well. Another rarer syndrome, known as cerebellar ataxia, leads to loss of balance and unsteadiness in movement of the arms and legs.

Of course, a diagnosis of SCLC or NSCLC is not solely assessed on the occurrence of syndromes or symptoms. Rather, a series of various tests and imaging scans are used to diagnose both SCLC and NSCLC. A patient's prognosis and treatment options heavily depend upon a variety of factors, including the type of lung cancer, stage of development, presence of symptoms, and the patient's general health.

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