Smoking causes most cases (around 90%) of lung cancer. The risk depends on the number of cigarettes you smoke each day and for how long you have smoked. Being around the smoke from other people (secondhand smoke) also raises your risk of lung cancer. But some people who do not smoke and have never smoked do develop lung cancer.
Research shows that smoking marijuana may help cancer cells grow. But there is no direct link between smoking marijuana and developing lung cancer.
Constant exposure to high levels of air pollution and drinking water that has a high level of arsenic can increase your risk of lung cancer. A history of radiation therapy to the lungs can also increase risk.
Working with or near cancer-causing chemicals or materials can also increase risk. Such chemicals include:
Chemicals such as uranium, beryllium, vinyl chloride, nickel chromates, coal products, mustard gas, chloromethyl ethers, gasoline, and diesel exhaust
Certain alloys, paints, pigments, and preservatives
Products using chloride and formaldehyde
Early lung cancer may not cause any symptoms. Symptoms you should watch for include:
These symptoms can be due to other, less serious conditions. It is important to talk to your health care provider if you have symptoms.
Exams and Tests
The doctor will perform a physical exam and ask about your medical history. You will be asked if you smoke, and if so, how much you smoke and for how long. You will also be asked about other things that may have put you at risk of lung cancer, such as exposure to certain chemicals.
When listening to the chest with a stethoscope, the doctor may hear fluid around the lungs. This may suggest cancer.
Tests that may be done to diagnose lung cancer or see if it has spread include:
The following treatments are mostly used to relieve symptoms caused by NSCLC:
Laser therapy - a small beam of light burns and kills cancer cells
Photodynamic therapy - uses a light to activate a drug in the body, which kills cancer cells
You can ease the stress of illness by joining a cancer support group. Sharing with others who have common experiences and problems can help you not feel alone.
The outlook varies. Most often, NSCLC grows slowly. In some cases, it can be very aggressive and cause rapid death. The cancer may spread to other parts of the body, including the bone, liver, small intestine, and brain.
Chemotherapy has been shown to prolong life and improve the quality of life in some patients with stage IV NSCLC.
Cure rates are related to the stage of disease and whether you are able to have surgery.
Stage I and II cancers have the highest survival and cure rates.
Stage III cancer can be cured in some cases.
Stage IV cancer that has returned is almost never cured. The goals of therapy are to extend and improve quality of life.
When to Contact a Medical Professional
Call your health care provider if you have symptoms of lung cancer, particularly if you smoke.
If you smoke, now is the time to quit. If you are having trouble quitting, talk with your doctor. There are many methods to help you quit, from support groups to prescription medicines. Also, try to avoid secondhand smoke.
If you smoke or used to smoke, talk with your doctor about getting screened for lung cancer. To get screened, you need to have a CT scan of the chest.
Johnson DH, Blot WJ, Carbone DP, et al. Cancer of the lung: non-small cell lung cancer and small cell lung cancer. In: Abeloff MD, Armitage JO, Niederhuber JE, et al., eds. Abeloff's Clinical Oncology. 4th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2008:chap 76.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Non-small cell lung cancer. Version 4.2014. Available at http://www.nccn.org/professionals/physician_gls/pdf/nscl.pdf. Accessed August 31, 2014.
National Cancer Institute: PDQ Non-Small Cell Lung Cancer Treatment. Bethesda, MD: National Cancer Institute. Date last modified 06/30/2013. Available at: http://cancer.gov/cancertopics/pdq/treatment/non-small-cell-lung/Patient. Accessed August 31, 2014.
Yi-Bin Chen, MD. Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.