Most people in the United States have had their lives or the lives of a close family member affected by cancer. Despite the familiarity with the disease, it often surprises people to hear that lung cancer remains the leading cause of cancer related death in the United States for both women and men. In fact, each year more people lose their lives as a result of lung cancer than from breast cancer, prostate cancer, colorectal cancer, and pancreatic cancer combined. In 2010, it was estimated that $12.1 billion was spent on the care of people with lung cancer.
What is Lung Cancer?
Lung cancer is an uncontrolled growth of lung cells. The term “lung cancer” is only used for cancers that start within the lung and not for cancers that begin in other organs and spread to the lungs. The abnormal growth of the lung cells is caused by damage to the cells’ DNA. This damage is most frequently caused by tobacco smoking, but can be linked to other exposures, including asbestos and radon gas. As the cells grow and divide, they can damage the lung. Over time, some of the cells may be able to break free and travel to the lymph nodes in the chest or even to other portions of the body including the brain, liver, and bones.
There are two major types of lung cancer: small cell lung cancer and the more common non-small cell lung cancer. Adenocarcinoma, squamous cell carcinoma, and large cell carcinoma are all types of non-small cell lung cancer. Carcinoid tumor is an uncommon third type of lung cancer that is less clearly linked to cigarette smoking. Mesothelioma is a type of cancer arising in the lining of the lung that occurs in patients exposed to asbestos.
Staging, Symptoms, and Treatment of Lung Cancer
As with other cancers, lung cancer is often grouped into “stages” based on the extent of involvement. Small-sized tumors located within the lung are considered stage 1. With lymph node involvement, the stage increases to stage 2 or 3. If the cancer spreads to the other lung or outside of the chest, the cancer is considered to be in stage 4 (often called “metastatic”). As the stage increases, the chance of curing the disease decreases. At present, only about 15 percent of patients are diagnosed with the cancer in stage 1.
Typically, people will have minimal or no symptoms when the cancer is in the most curable stage, stage 1. As the cancer spreads, people may develop spells of coughing blood, shortness of breath, fatigue, unexplained weight loss or night sweats.
Treatment decisions are complex. In general, for patients diagnosed in stage 1, treatment options may include surgery to remove the portion of lung containing the tumor. If unable to perform surgery due to physical condition or patient preference, radiation therapy is used. For stage 2, chemotherapy is often added to surgery or radiation therapy. Stage 3 is often treated with radiation therapy and chemotherapy. Stage 4 is typically treated with chemotherapy and radiation treatments to involved areas causing discomfort.
Risks for Lung Cancer
The most important risk factor for developing lung cancer is a history of tobacco smoking. In 1957, Surgeon General Leroy Burney announced for the first time the official position of the U.S. Public Health Service that there was a causal relationship between cigarette smoking and lung cancer. Over the next 57 years, considerable effort has been spent on smoking prevention and cessation programs. While smoking rates have declined since the 1950s, it is estimated that even today, 94 million Americans are either actively smoking or have smoked in the past and are at increased risk for lung cancer. Around 85 percent of lung cancers can be linked to cigarette smoking although other exposures, including asbestos, radon, diesel fumes, and welding fumes also increase risk for developing the disease. The risk of developing lung cancer increases with age. Those with a first degree family member with lung cancer are at increased risk as are those who have personally had lung cancer in the past.
Prevention and Screening
Abstaining from cigarette smoking is the only way to prevent lung cancer. For those who smoke, it is never too late to stop smoking. The risk of developing lung cancer decreases the longer cigarettes are avoided.
Screening refers to detection of cancers in people without symptoms. Unlike breast or colorectal cancer, a screening test for lung cancer has not been available until recently. In 2011, a large study called the National Lung Cancer Screening Trial (NLST) was published. This study demonstrated that a yearly low-radiation CT scan of the chest in people at increased risk for lung cancer can significantly reduce number of people dying from the disease. As a result, lung cancer screening has been recommended by the US Preventive Services Task Force (USPSTF) for people in the following group:
- Age 55-80 years
- History of smoking at least 30 pack-years (average of 1 pack per day for 30 years)
- Actively smoking or quit within the last 15 years
Lung cancer screening is now being offered at The University of Vermont Medical Center. The screening program is one of only a handful of sites in the United States currently accredited by the American College of Radiology to perform and interpret the results. If you meet the above criteria, speak with your health care provider about lung cancer screening. If you are smoking and looking to quit, contact the Vermont Quit Line at (802) QUIT-NOW or online at 802quits.org.
Garth Garrison, MD, is a pulmonary disease physician at The University of Vermont Medical Center and an assistant professor at the Larner College of Medicine at UVM.