Lung Cancer Facts

The Lungs and Lymph System

To understand lung cancer, it helps to know more about the lungs and lymph system.
The lungs—a pair of cone-shaped organs made up of spongy, pinkish-gray tissue—are part of the respiratory system. They take in oxygen, which body cells need to live and carry out their normal functions, and they rid the body of carbon dioxide, a waste product of the cells. Air travels down your trachea, through your bronchi and bronchioles, into your alveoli, and back out again. The right lung has three sections called lobes, and is a little larger than the left lung. The left lung has two lobes and is smaller because the heart takes up room on that side of the body.

Lung Diagram

The American Cancer Society’s estimates for lung cancer in the United States for 2014 are:

  • About 224,210 new cases of lung cancer (116,000 in men and 108,210 in women)
  • An estimated 159,260 deaths from lung cancer (86,930 in men and 72,330 among women), accounting for about 27% of all cancer deaths

Lung cancer is by far the leading cause of cancer death among both men and women. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined.

What is Lung Cancer?

Lung cancer is cancer that begins in the lungs.  (Cancer that begins somewhere else in the body and spreads to the lungs is different from lung cancer.) Normally, lung cells divide to produce more cells only when the body needs them. Lung cancer occurs when cells divide and form more cells uncontrollably, creating a mass of tissue called a tumor. Malignant tumors are cancers, which can invade and damage nearby lymph nodes, tissues and organs. Cancer cells can also break away from a malignant tumor and enter the bloodstream, spreading to other parts of the body where they can form new tumors Build-up of fluid around involved lung, or pleural effusion, could be an indicator of lung cancer.

Lung cancer can start in the cells lining the bronchi (the two main airways that branch off the trachea, or windpipe) or within the lungs—in the bronchioles (smaller branches) or alveoli (air sacs). It often takes years to develop.

The cancer cells can enter the lymph system and begin to grow in lymph nodes around the bronchi and in the mediastinum (area between the lungs). If lung cancer has reached the lymph nodes, it is likely to have spread to other parts of the body as well.

It is also possible to have a non-cancerous (benign) tumor in the lung which rarely poses a threat to life. However, such lesions still may need to be removed to make sure that no malignancy is present in that area.

What Causes Lung Cancer?

In most cases lung cancer is caused by cigarette smoking. Tobacco smoke contains many carcinogens, substances that damage lung cells; over time, these damaged cells can become cancerous. The more people smoke, the higher their risk of developing lung cancer. As soon as smokers quit, the risk of developing lung cancer begins to slowly decrease. The earlier smokers quit, the more their risk of developing lung cancer approaches that of a person who never smoked.

Exposure to other people’s tobacco smoke, whether at home or in the workplace, increases the risk of developing lung cancer among non-smokers. This is commonly referred to as second hand smoke.

Exposure in the workplace to certain carcinogens, such as asbestos, also increases the risk of developing lung cancer. The risk is especially high for workers who smoke. People should carefully follow work and safety rules to reduce their exposure to workplace carcinogens.

Also at increased risk for developing lung cancer are workers (especially those who smoke) exposed to high levels of the radioactive gas, radon, in some underground mines.

Types of Lung Cancer

There are two main types of lung cancer:

  • Non-small cell lung cancer (NSCLC) which accounts for about 85 percent of all lung cancers.
  • Small cell lung cancer (SCLC) which makes up about 15 percent of all lung cancers.

Non-small Cell Lung Cancer

Non-small cell lung cancer is classified into three main subtypes.

  • Squamous cell carcinoma, also called epidermoid carcinoma, is the most common type of lung cancer in the United States and many other countries. This disease often beings in the bronchi, or large air tubes leading to the lungs. It usually spreads less quickly that other types of lung cancer. Squamous cell carcinomas account for about 25 to 30 percent of all lung cancers.
  • Adenocarcinoma usually begins along the outer edges of the lungs and under the lining of the bronchi. This is the most common type of lung cancer in women and in people who have never smoked. About 40 percent of lung cancers are adenocarcinomas. The incidence of adenocarcinoma is on the rise.
  • Large cell carcinoma can occur in any part of the lung but is most commonly found near the outer region of the lung. Large cell carcinomas tend to grow and spread faster than the other two types. This type accounts for about 10 to 15 percent of lung cancers

Small Cell Lung Cancer

Small cell lung cancer usually starts in the bronchi. Although the cancer cells are small, they grow very quickly and create large tumors. These tumors often spread rapidly to other parts of the body, including the brain, liver, and bone. Most small cell lung cancers spread outside the lung before they are discovered. Small cell lung cancer occurs almost exclusively in heavy smokers.

What are the symptoms of lung cancer?

At first, lung cancer usually doesn’t cause symptoms. The symptoms of lung cancer can take years to develop. They are often mistaken for less serious problems thought to be related to tobacco use alone. Of course, it is important to remember that lung cancer can develop even in people who haven’t smoked. Doctors sometimes discover it in people without symptoms after a chest x-ray for another medical reason. Usually, however, lung cancer is found after the growing tumor causes symptoms to appear. The following are the most common symptoms for lung cancer. However, each individual may experience symptoms differently.

A cough, which is the most common symptom of lung cancer, is likely to occur when a tumor irritates the ling of the airways or blocks the passage of air. The person may have a “smoker’s cough” that worsens.

Another symptom is constant chest pain. Others may include shortness of breath, wheezing, repeated bouts of pneumonia or bronchitis, coughing up blood or hoarseness.

A tumor that presses on large blood vessels near the lung can cause swelling of the neck and face. If the tumor presses on certain nerves near the lung, it can cause pain and weakness in the shoulder, arm or hand. Problems with vision could be an indirect sign of nerve involvement as well.

In addition, there may be symptoms that don’t seem to be related to the lungs. Like all cancers, lung cancer can cause fatigue, loss of appetite and loss of weight. If the disease spreads elsewhere, it may cause headache, pain or bone fractures.

Other symptoms result from substances the lung cancer cells make. For example, certain lung cancer cells produce a substance that sharply reduces the level of sodium (a component of salt) in the blood. This can cause many symptoms, including confusion and sometimes even coma.

None of these, however, is a sure sign of lung cancer. Only a physician can tell whether a patient’s symptoms are caused by cancer or another problem.


At Delta Medix we have a comprehensive, multidisciplinary program to detect, treat and educate high risk individuals against lung cancer based on the findings of the National Lung Screening Trial (NLST). To see if you qualify for a LDCT lung screening at Delta Medix (click here)