Lung cancer is the third most common type of cancer and the most common cause of fatalities in U.S. Generally, lung cancer affects more males than females.

Lung cancer is a disease that occurs when the cells divide uncontrollably in lungs leading to the growth of tumors. This tumor can either be local or may spread to other areas of body. The main symptom of lung cancer occurs as the person is unable or has reduced ability to breathe.[i]

What is lung cancer?

Cancer leads to alteration in the cells. Due to these changes, the cells start to grow quickly and abnormally.

Where normal cell would die at a certain part of their life cycle abnormal or cancer cells would not. They would continue to replicate and multiply leading to a buildup of cells. Consequently, a tumor develops.

Types of lung cancer

Lung cancer has been classified into two types depending on the size of cell (when seen under a microscope). The types of lung cancer are as follows:

Non-small cell lung cancer

This type is more common than small cell lung cancer affecting about 84% people of U.S. It has three subtypes:

  1. Adenocarcinoma
  2. Large cell carcinoma
  3. Squamous cell cancer

Small cell lung cancer

This is the less common type affecting about 13% of the U.S individuals with cancer. The growth of this type of cancer is more as compared to non-small cell lung cancer.[ii]

Symptoms and signs

The symptoms of lung cancer may or may not appear in people until a later stage. The symptoms of lung cancer are usually similar to the ones encountered in a respiratory infection.

Some of the symptoms that may appear in people with this disease include:

  1. Chest infections that may occur frequently
  2. Pain in chest
  3. Shortness of breath
  4. Bronchitis or pneumonia
  5. Wheezing sounds
  6. Swollen lymph nodes on chest
  7. Persistent cough that may worsen over time

Other more severe symptoms that may occur at later stages include:

  1. Severe pain in chest and bones
  2. Cough with blood
  3. Headache
  4. Bone fractures
  5. Weight loss
  6. Fatigue
  7. Clotting of blood
  8. Loss of appetite

Causes of Lung Cancer

The major cause of lung cancer is smoking or exposure to cigarette smoke. People who smoke or individuals who have an exposure to secondhand have higher risk of developing lung cancer. However it can also occur in non-smokers. There is no confirmed cause of lung cancer.

Smoking damages the cells lining the lungs. The carcinogens present in cigarette smoke are cancer-causing substances and lead to alterations in lung tissue. Although the body tries to repair these lung cells but overtime the damage becomes too much and eventually lung cancer develops.

Risk factors


As already stated, cigarette smoking is the most common risk factor for lung cancer. About 80 to 90% of lung cancer fatalities in U.S are associated with cigarette smoking. The carcinogens present in cigarette not only put you at risk of lung cancer but also cancer of cervix, stomach, colon, mouth, throat and myeloid leukemia.


Radon is the second main risk factor for lung cancer. About 20,000 cases of this disease are linked to radon exposure. Substances like silica, chromium, asbestos, arsenic, and diesel exhaust increase the chances of getting lung cancer.


This disease may also be inherited. Close relatives including children, siblings and parents might have a higher risk of developing the disease.

Radiation Therapy

Patients of other types of cancers that may have been exposed to radiation therapy, especially to the chest, have increased chances of getting this type of cancer.


Some dietary supplements such as beta-carotene or arsenic present in drinking water can increase your chances of developing lung cancer. [iii]

Tests to diagnose lung cancer

Different tests that can be performed to diagnose lung cancer include:

  1. Sputum cytology – sometimes the lung cancer cells are present in the sputum of the patient and by checking under microscope one might be able to tell if the patient has the chances of lung cancer.
  2. Imaging tests – An X-ray, CT-scan or MRT can be done to reveal a tumor. A PET scan can be performed to determine how much the cancer has spread in the body.
  3. Biopsy – in this test a tissue is removed from the affected part of the body and is studied for the presence or absence of cancer cells. In case of lung cancer, usually bronchoscopy is performed in which the doctor observes the abnormal parts of lung by means of a bronchoscope (a lighted tube with a camera on one end). Needle biopsy is another option, where suspicious cells are collected by a needle.
  4. Mediastinoscopy – it is another procedure where an incision is made by surgical tools at the base of neck and tissue samples are taken from lymph nodes.

Treatment of Lung Cancer

A treatment plan is usually selected depending on various factors including the type of cancer, stage of disease and the overall health of the patient.


If the lung cancer cells are confined to a specific part of the lung surgery is an option. In lung cancer surgery the part of lung with cancer is removed. Following types of surgeries can be performed by the doctor:

Lobectomy – in this surgery that entire lobe of one lung is removed.

Segmental resection – this surgery involves the removal of a large part of lung (but not the entire lobe)

Wedge resection – involves the removal of only a small portion of lung containing the tumor.

Pneumonectomy – involves the removal of an entire lung

Radiation therapy

If a person is on an advanced stage of lung cancer he may be treated with radiation therapy. It may also be combined with surgery or chemotherapy depending on the type and severity of cancer. In this therapy, high beams of energy are used to kill the abnormal cancer cells. In cases where the cancer cells have been spread in the whole body radiation is the treatment option for relieving the symptoms.


This treatment involves the use of drugs against the cancer cells. One or more agents can be used to treat the patient. These drugs may either be taken orally or injected intravenously. Chemotherapy may also be given after surgery to kill any remaining cancer cells. This helps to shrink the tumor and kill the cancer cells.[iv]

Palliative care

This is Supportive treatment that involves minimizing the signs and symptoms of the disease to ensure a good quality of life for the patient.