Lung Cancer

The American Cancer Society estimates that about 219,440 new cases of lung cancer were diagnosed in 2009, and that 159,390 people died of the disease in the same time period. Not counting skin cancers, lung cancer is the second most common cancer in both men and women, accounting for 15% of all new cancers.  Lung cancer also is the leading cause of cancer death, accounting for about 28% of all cancer deaths.

Smoking is the greatest risk factor for lung cancer, and about 87% of all lung cancer deaths are attributed to smoking.  The risk increases with the amount of time and number of packs a person smokes. Breathing in smoke created by others (second-hand smoke) is another important risk factor for lung cancer; a non-smoker who lives with a smoker has about a 20% to 30% increased risk of developing the disease. Other environmental risk factors include exposure to radon gas, asbestos, radioactive ores, arsenic, diesel exhaust, and air pollution. Prior radiation therapy to the chest can also increase the risk of developing lung cancer. A personal or family history of lung cancer also is a risk factor for the disease.

The two major types of lung cancer are small cell lung cancers (SCLC), which originates in small cells within the lung, and non-small cell lung cancer (NSCLC), which arises in other types of cells within the lung.

Non-small Cell Lung Cancer

There are three subtypes of NSCLC, which together account for about 85% to 90% of lung cancers. Squamous cell carcinoma accounts for about 25% to 30% of all lung cancers and is often linked to a history of smoking. About 40% of lung cancers are adenocarcinoma, and people with this type of cancer tend to have a better prognosis than those with other types of lung cancer. Large-cell carcinoma, which accounts for about 10% to 15% of lung cancers, tends to grow and spread quickly, making it difficult to treat.

Treatments for NSCLC include surgery, radiation therapy, chemotherapy, and targeted therapy. Smaller lung tumors may also be treated with localized therapies that utilize electricity, light-activated drugs, or lasers. The choice of therapy depends on several factors, including the stage of disease, tumor size and location, and the patient’s overall health. Surgery is usually recommended for treatment of early-stage lung cancers, and it provides the best chance of a cure for NSCLC. Radiation therapy is the main treatment for lung cancers, especially if surgery is not an option due to the size or location of the tumor or the patient’s health. It may also be used after surgery to kill any remaining cancer cells or to relieve symptoms of advanced lung cancer. Chemotherapy may be used prior to surgery to reduce the size of the tumor, after surgery to eliminate any remaining cancer cells, or as the primary treatment for more advanced cancers.

The 5-year survival rate for NSCLC ranges from 49% to the earliest-stage disease to only 1% for the most advanced forms of the disease.

Small Cell Lung Cancer

SCLC accounts for about 10% to 15% of all lung cancers.  Other names for SCLC include oat cell cancer, oat cell carcinoma, and small cell undifferentiated carcinoma. SCLC often starts in the bronchi, near the center of chest.  It tends to spread quickly throughout the body, making it difficult to treat.

SCLC is almost always caused by smoking, and it occurs only rarely in people who haven’t smoked. Other risk factors are similar to those for NSCLC and include second-hand smoke, exposure to radon gas, asbestos, radioactive ores, arsenic, diesel exhaust, and air pollution; prior radiation therapy; and a personal or family history of lung cancer.

Depending on the stage and location of disease and the patient’s other health factors, SCLC may be treated with chemotherapy, radiation therapy or surgery. Chemotherapy is the main treatment for patient’s who are healthy enough to tolerate it. Patients with limited disease may be treated with radiation.  Surgery is used in only about 5% of SCLC patients, when the cancer is found as one localized tumor that has not spread.

The 5-year survival rate for SCLC ranges from 31% to early-stage disease to only 2% for the most advanced cases.

Adapted from the American Cancer Society’s “Detailed Guide: Lung Cancer – Small Cell” and “Detailed Guide: Lung Cancer – Non-small Cell”

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