What is lung cancer?

Primary lung cancer is cancer that usually starts in the lining of the bronchi, but can also begin in other areas of the respiratory system, including the trachea, bronchioles, or alveoli. Lung cancers are believed to develop over a period of many years. Nearly all lung cancers are carcinomas, a cancer that begins in the lining or covering tissues of an organ.

Many cancers originating outside of the lung can metastasize, or spread, to the lung. These are referred to as "lung - metastases" and are not to be confused with primary lung cancer arising within lung tissue.

Lung cancers are generally divided into two types:

• Nonsmall cell lung cancer is more common than small cell lung cancer. The three main kinds of nonsmall cell lung cancer are named for the type of cells in the tumor:
  
  
  • Squamous cell carcinoma, also called epidermoid carcinoma, is the most common type of lung cancer in men. It often begins in the bronchi and usually does not spread as quickly as other types of lung cancer.
    
    
  • Adenocarcinoma usually begins along the outer edges of the lungs and under the lining of the bronchi. It is the most common type of lung cancer in women and in people who have never smoked.
    
    
  • Large cell carcinomas are a group of cancers with large, abnormal-looking cells. These tumors usually begin along the outer edges of the lungs.
    
    
• Small cell lung cancer, sometimes called oat cell cancer because the cancer cells may look like oats when viewed under a microscope, grows rapidly and quickly spreads to other organs.

It is important to find out what kind of lung cancer a person has. The different types of carcinomas, involving different regions of the lung, may cause different symptoms and are often treated differently.

What are the symptoms of lung cancer?

The following are the most common symptoms for lung cancer. However, each individual may experience symptoms differently.

Lung cancer usually does not cause symptoms when it first develops, but they often become present after the tumor begins growing. A cough is the most common symptom of lung cancer. Other symptoms include:

• constant chest pain

• shortness of breath

• wheezing

• recurring lung infections, such as pneumonia or bronchitis

• bloody or rust colored sputum

• hoarseness

• a tumor that presses on large blood vessels near the lung can cause swelling of the neck and face

• a tumor that presses on certain nerves near the lung causing pain and weakness in the shoulder, arm, or hand

• fever for unknown reason

Like all cancers, lung cancer can cause:

• fatigue
  
  
• loss of appetite
  
  
• loss of weight
  
  
• headache
  
  
• pain in other parts of the body not affected by the cancer
  
  
• bone fractures

Other symptoms can be caused by substances made by lung cancer cells - referred to as a paraneoplastic syndrome. Certain lung cancer cells produce a substance that causes a sharp drop in the level of sodium in the blood, which can cause many symptoms, including confusion and sometimes even coma.

None of these symptoms is a sure sign of lung cancer. Only a physician can tell whether a patient's symptoms are caused by cancer or by another problem. Consult your physician for a diagnosis.

What are the risk factors for lung cancer?

A risk factor is anything that increases a person's chance of getting a disease such as cancer. Different cancers have different risk factors. Several risk factors make a person more likely to develop lung cancer:

• Smoking is the leading cause of lung cancer, with more than 80 percent of lung cancers thought to be a result of smoking.

Additional risk factors include:

• secondhand smoke - breathing in the smoke of others

What is a risk factor? A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases, including cancers, have different risk factors. Although these factors can increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors. But, knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.

• asbestos exposure
  
  

• cancer-causing agents in the workplace, including:
  
  
  • radioactive ores such as uranium
  • arsenic
  • vinyl chloride
  • nickel chromates
  • coal products
  • mustard gas
  • chloromethyl ethers
    
    
• radon - a radioactive gas that cannot been seen, tasted, or smelled. It is produced by the natural breakdown of uranium.

• family history

• personal history of lung cancer or head/neck cancer

• smoking marijuana cigarettes, which:
  
  
  • contain more tar than tobacco cigarettes.
    
    
  • are inhaled very deeply.
    
    
  • are smoked all the way to the end where tar content is the highest.
    
    
  • Because marijuana is an illegal substance, it is not possible to control whether it contains fungi, pesticides, and other additives.
    
    

How is lung cancer diagnosed?

In addition to a complete medical history to check for risk factors and symptoms, and a physical examination to provide other information about signs of lung cancer and other health problems, procedures used to diagnose lung cancer may include:

• chest x-ray - to look for any mass or spot on the lungs.

• computed tomography scan (Also called a CT or CAT scan.) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.

• sputum cytology - a study of phlegm (spit) cells under a microscope.

• needle biopsy - a needle is guided into the mass while the lungs are being viewed on a CT scan and a sample of the mass is removed and evaluated in the pathology laboratory under a microscope.

• bronchoscopy - the examination of the bronchi (the main airways of the lungs) using a flexible tube (bronchoscope). Bronchoscopy helps to evaluate and diagnose lung problems, assess blockages, obtain samples of tissue and/or fluid, and/or to help remove a foreign body.

• mediastinoscopy - a process in which a small cut is made in the neck so that a tissue sample can be taken from the lymph nodes (mediastinal nodes) along the windpipe and the major bronchial tube areas to evaluate under a microscope.

• x-rays and scans of the brain, liver, bone, and adrenal glands - to determine if the cancer has spread from where it started into other areas of the body.

• PET scans - a tracer is given intravenously that collects at tumor sites, and can be indentified by the scanner.

Other tests and procedures may be used as well.

Treatment for lung cancer:

Specific treatment for lung cancer will be determined by your physician based on:

• your age, overall health, and medical history
• extent of the disease
• your tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

Surgery, radiation therapy, and chemotherapy may be used in the treatment of lung cancer.

• surgery
  Three main types of surgery are most often used in lung cancer treatment. The choice depends on the size and location of the tumor, the extent of the cancer, the general health of the patient, and other factors.
  
  
  • segmental or wedge resection - to remove only a small part of the lung
  • lobectomy - removal of an entire lobe of the lung
  • pneumonectomy - removal of an entire lung
    
    
• radiation therapy (also called radiotherapy) - the use of high-energy rays to damage cancer cells and stop them from growing and dividing.

• chemotherapy - the use of drugs to kill cancer cells.