Approximately 80 percent of people with lung cancer have non-small cell lung cancer. Depending on the type of cancer cell present, non-small cell cancer is in turn divided into several subtypes. Squamous cell carcinoma begins in thin, flat surface cells that line the respiratory tract, and is the most common type. Adenocarcinoma forms in cells that have a secretory or glandular function. Adenosquamous carcinoma begins in flattened cells that also have secretory properties. In sarcomatoid carcinoma, cells look markedly abnormal under the microscope. Carcinoid tumors grow slowly, and release hormones when stimulated by the nervous system. Cells in salivary glands in larger airways can also become cancerous.

Cancer cells in non-small cell lung cancer can produce hormones or hormone-like substances to cause certain conditions called paraneoplastic syndromes. These conditions include high blood calcium levels, abnormal clotting, overgrowth of certain bones and those in the fingertips in particular, and abnormal breast growth in men.

People with non-small cell lung cancer tend to be diagnosed later in the course of their disease, making these a difficult group of cancers to treat. The type of cancer, its location and stage, the presence of symptoms, and the patients overall condition and ability to withstand treatment all affect the ultimate outcome. Symptoms include breathlessness, chest pain, coughing up of blood, fatigue, fever and weight loss. A diagnosis is typically made by imaging, a lung biopsy, and blood tests.

Early non-small cell lung cancer can be treated by surgery. Once it spreads to surrounding chest tissues and to lymph nodes, chemotherapy and radiotherapy are frequently employed. Newer forms of treatment include laser therapy, photodynamic therapy, and biotherapy. The five-year survival rate for early non-small cell lung cancer is close to 50 percent; five-year survival drops to about two percent in the most advanced cases. A number of clinical trials are underway to find better treatment options. The National Cancer Institute website provides information on such trials.