Lung cancer is the leading cause of cancer deaths in both men and women worldwide. Comparatively rare in the early 20^th century, lung cancer cases soared with the introduction of mass-produced cigarettes.

About 87 percent of lung cancers are due to tobacco products, either through direct smoking or passive exposure to smoking, according to the American Cancer Society (ACS). The number of cigarettes smoked per day and the length of time a person smokes directly impacts the risk of developing lung cancer. Men have a slightly greater chance of developing lung cancer - 1 in 12 - as compared to women who have a 1 in 17 chance. Lung cancer will account for 12 percent of all new cases of cancer.

The ACS estimates that about 213,000 new cases of lung cancer will be diagnosed in 2007. In the same year, lung cancer will be responsible for more than 160,000 deaths. The disease causes more deaths than colon, breast and prostate cancers combined. Although the prognosis for lung cancer is often poor, there are currently about 330,000 long-term survivors.

There are two basic types of lung cancer: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). The type of lung cancer is important because it affects how the disease is treated. Most cases of lung cancer are NSCLC, which generally grows more slowly than SCLC.

Both types of lung cancer can be very difficult to treat. By the time patients report symptoms, the disease has often spread to other parts of the body. Common symptoms of lung cancer include persistent cough (often called “smoker's cough”), breathing problems, blood in sputum, pneumonia and respiratory infections, chest pain, weight loss and fatigue.

When lung cancer is suspected, diagnostic tests such as a chest x-ray, MRI, CAT scans and PET scans can be used to determine the location of the cancer. These tests, as well as bone scans may be performed to determine if and where the cancer has spread (metastasis). A sample of lung tissue may be obtained through a needle biopsy to analyze the cells for presence and type of cancer.

If the cancer is detected early and it remains in the lung, surgery may be an option. For lung cancer that has spread, chemotherapy and radiation therapy are standard treatment methods. Small cell lung cancer, which metastasizes quickly, can be treated with brain radiation to prevent spreading of the cancer to the brain.

Because smoking is such a strong risk factor for developing lung cancer, quitting smoking can greatly reduce the likelihood of lung cancer. The incidence and death rates for lung cancer have declined in the last several years, in part due to the decreased trend in cigarette smoking.

Survival rates of lung cancer vary with the type and stage of the disease. The one-year survival rate for lung cancer has increased slightly during the past decade, primarily due to improved treatments. However, about 60 percent of the people diagnosed with lung cancer will die within one year of their diagnosis. Within two years, nearly 75 percent will die from the disease. Currently, the ACS estimates there are about 330,000 individuals who have survived lung cancer.

Whether to screen for lung cancer remains an ongoing debate among scientists. Some studies suggest that screening with certain tests, such as CAT scans or e-rays, may help detect early stage lung cancer. However, other studies found no significant reduction in deaths from lung cancer due to screening tests. Additional studies are needed to determine definitively the value of screening for lung cancer.

Patients should discuss the use of screening tests with their physicians. Currently, the best method to combat lung cancer of all types is by refraining from or quitting smoking.