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Lung cancer tops the list of cancers which can cause death. According to the National Cancer Institute, around 228,190 Americans were diagnosed with lung cancer in 2012 of which an estimated 158,480 succumbed to their illness.
Lung cancer usually affects people above the age of 60.
Exposure to second hand smoke can also lead to lung cancer. Among other risk factors, genetics also plays an important role with the cancer showing a predisposition to affect family members of patients already suffering from the disease.
Some of the common symptoms of lung cancer are:
- Severe coughing or cough lasting for a long duration
- Pain in the chest, back or shoulders, often as a result of coughing
- Difficulty in breathing in or exhaling of air and in swallowing
- Change in voice often accompanied with hoarseness
- Presence of stridor
- Changes in the color of sputum
- Coughing out of blood tinged sputum
If the cancer has metastasized to areas beyond the lungs, like to the brain or to the bones, additional symptoms are seen depending upon the site of metastasis. There may be swelling and pain of the regional lymph nodes. If the cancer has reached the brain, patient may complain of dizziness, headache, or even seizures. Metastasis to bones often presents as fractures. Metastasis to liver may present as jaundice and enlargement of the liver.
Classification of lung cancer
Lung cancer is broadly classified into:
- Non-small cell lung cancer (NSCLC)
- Small cell lung cancer (SCLC)
NSCLCs can be further divided into four different types depending upon the nature of cells. They are:
- Squamous cell carcinoma: It is also called as epidermoid carcinoma. This type of cancer develops in the lining of the bronchial vessels and is the most common type of lung cancer in men.
- Adenocarcinoma: It develops in the mucus producing glands of the lungs and primarily affects women and non-smokers.
- Bronchioalveolar carcinoma: It is a rare form of lung cancer developing in the terminal bronchioles which open into the air sacs.
- Large cell undifferentiated carcinoma: This type of cancer develops near the outer surface of the lungs.
SCLC are cancers composed of small cells. They proliferate rapidly and metastasize quickly. Almost all of SCLCs are due to smoking.
The different types of lung cancers are staged according to their spread. The treatment and prognosis of these cancers depends upon the stage of the cancer when it is first diagnosed.