What is Lung Cancer?

Causes, Symptoms, Diagnosis and Treatment


Lung cancer arises when a series of mutations in normal lung cells cause them to become abnormal and grow out of control. These changes can take place anywhere from the bronchus (the windpipe), down to the small air sacs in the periphery of the lungs where oxygen exchange takes place.

How Common is Lung Cancer?

Once uncommon, the surge in smoking of the 20th century has contributed to a tremendous rise in the incidence of lung cancer.

Lung cancer is now the leading cause of cancer death in men and second leading cause of cancer death in women worldwide. On the bright side, with widespread awareness of the risks of smoking, many hope these numbers will decrease in the future.

Causes of Lung Cancer

Tobacco use is responsible for almost 90% of lung cancer cases. That being said, those who have never smoked or quit long ago, may develop lung cancer as well. Common causes include radon exposure in the home, workplace chemicals such as asbestos, and environmental pollutants including secondhand smoke.

Symptoms of Lung Cancer

Lung cancer most commonly presents with a cough that does not go away over time.

Sometimes it shows up with vague symptoms, such as fatigue, and about 25% of the time, there are no symptoms at all. Since lung cancer is common, anyone, especially those who smoke, should seek prompt medical attention for any symptom that is new or unexplained. The most common symptoms include:

More about symptoms:

Lung Cancer Diagnosis

Lung cancer is often suspected initially from a chest x-ray done to evaluate a cough or chest pain. Further studies are performed to determine if the abnormality is benign (non-cancerous), or malignant (cancerous.) If these show cancer, further tests may be performed to see whether the cancer has spread (metastasized) to other areas in the body.

Types of Lung Cancer

There are two major types of lung cancer. Non-small cell lung cancer accounts for roughly 80% of cases. Small cell lung cancer, which is usually causes by smoking, comprises 15% of lung cancers and tends to spread quickly. Rare forms of lung cancer include carcinoid tumors and mesothelioma.

    Stages of Lung Cancer

    Non small cell cancer is divided into stages from 1 to 4 depending on how far the cancer has spread. Stage 1 is localized. Stage 2 has spread locally, often to a lymph node. Stage 3A and Stage 3B involves further spread locally but beyond the lung. Stage 4 indicates spread to another region of the body. Small cell cancer is separated into two stages based on whether the cancer is limited or extensive.

    How is Lung Cancer Treated?

    Depending upon the stage and type of lung cancer diagnosed, treatment may include surgery, chemotherapy, and/or radiation therapy. New treatments, often with fewer side effects, are becoming available that target lung cancer.

    What is My Prognosis?

    Caught early when it can be treated with surgery, lung cancer can be very curable. Sadly, the majority of people with lung cancer are diagnosed after the cancer has spread too far to do surgery. Even in this case (inoperable lung cancer,) treatment can increase length of survival, and sometimes result in long-term cancer free remission. Since people vary widely in their general health at the time of diagnosis, it can be discouraging and misleading to look at statistics. Your health care provider is a better source for looking at your individual situation.

    National Institute of Health. Medline Plus: Lung Cancer. Updated 09/12/12. http://www.nlm.nih.gov/medlineplus/lungcancer.html

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