Though the causes and risk factors of lung cancer are well defined, its symptoms tend to differ widely from individual to individual. This is probably because lung cancer is of different types and the symptoms of lung cancer come on late after the cancer has advanced.

The onset of symptoms makes the individual eligible to undergo diagnostic tests to detect the presence of cancer in the lungs. If the diagnosis confirms the presence of cancer, the treatment is immediately started.

Nowadays, anyone and everyone is a potential candidate for lung cancer. We breathe in the air about 16 times a minute, for the minutes, hours, and days that we live. That air was supposed to be clean and non-polluted.

Today the very air that we breathe in, is polluted with harmful gases, dust, and smoke (potential carcinogens), which drastically affects the lives of plants, animals, and humans.

Every time we breathe in, the delicate tissues in the lungs get exposed to these harmful contaminants in the air.

The constant exposure of the lung tissues to these deadly gases constantly keeps damaging the delicate lung tissues and cells. This vastly increases your risk of cellular DNA mutation causing normal cells to turn into cancer cells.

Lung cancer, also known as carcinoma of the lung or pulmonary carcinoma, is the third most common cancer after skin cancer in the United States. The “privilege” of being second highest goes to prostate cancer in men and breast cancer in women.

Besides being common, it has one of the lowest survival rates among all cancers. More than half of people with lung cancer die within one year after diagnosis. This makes it the leading cause of cancer deaths.

According to the American Cancer Society, the chances of a man developing lung cancer in his lifetime is about 1 in 16; and for a woman, the risk is about 1 in 17. Though these include tobacco smokers and nonsmokers, smokers are at a significantly higher risk.

Lung cancer causes and risk factors

Lung cancer starts to develop when cells in the lung change or undergo mutation. This mutation is mainly in the form of a permanent change in the DNA sequence of a gene in the cell.

Most often, this change in lung cells is triggered by the dangerous toxic pollutants that people breathe in. Even if you were exposed to these dangerous pollutants in the past but now live in a cleaner environment, your risk of lung cancer still remains.

The following are the factors that contribute to the etiology and risk of lung cancer.

1. Smoking

Smoking is the number one cause of lung cancer. The association between smoking and cancer is well established. Ninety percent of lung cancer cases are attributed to smoking. Tobacco smoke contains many chemicals that are carcinogenic.

If you are an active or a passive smoker, quitting smoking is the best thing you can do to protect your lungs. However, quitting smoking does not eliminate lung cancer risk immediately.

Passive smokers are those that breathe in the secondhand cigarette smoke which the active smoker has exhaled. Continuous exposure to secondhand smoke has many dangers and the risk of lung cancer is high on the list.

To eliminate or reduce your risk

2. Indoor air pollution

Our houses are usually polluted with a mixture of gases and particles produced due to burning. Exposure to smoke from solid fuel is associated with various lung diseases, including chronic obstructive pulmonary disease (COPD), acute respiratory infection, and lung cancer.

Gases caused by incomplete combustion include sulfur dioxide, carbon monoxide, carbon dioxide, and nitrogen oxide, as well as polycyclic aromatic hydrocarbons, formaldehyde, and heavy metals.

A study has reported that the mortality rate associated with lung cancer was higher among those who used smoky coal than among those who used smokeless coal.

Indoor pollution, therefore, can be a major cause and risk factor of lung cancer.

3. Radon

Radon is a naturally occurring, colorless, odorless, invisible radioactive gas that can cause lung cancer. Exposure to radon is the second-leading cause of lung cancer. It exists naturally in soil and comes about from the breakdown of uranium in soil and rocks..

It comes up through the soil and enters your houses through small gaps and cracks. This phenomenon is fairly common and one out of every 15 homes in the U.S. is exposed to radon exposure.

Exposure to radon combined with cigarette smoking produces a double whammy and greatly increases your lung cancer risk.

You can test your home for radon exposure with inexpensive, easy-to-use test kits sold at hardware stores.

4. Exposure to hazardous chemicals

Regular exposure to certain hazardous chemicals can be due to an occupational hazard or living in a highly industrial environment.

This poses a very high lung cancer risk. If you are working with materials such as asbestos, uranium, arsenic, cadmium, chromium, nickel, and petroleum products, you are in the danger zone.

If you are exposed to dust, gases, or hazardous chemicals at work or home, CDC has a useful post that can help you reduce your risk.

5. Particle pollution

Particle pollution of air refers to the presence of a mix of very tiny solid and liquid particles, which we breathe in. Exhaust smoke is one significant contributor to particle pollution of the atmosphere.

6. Genes

Genetic factors play a role in one’s chances of developing lung cancer. A family history of lung cancer greatly increases the risk of developing lung cancer.

The development of genetic factors as a risk involves shared environmental and lifestyle factors among family members.

Symptoms of lung cancer

Different people present with different symptoms of lung cancer.

  • The symptoms may be localized to the lungs
  • The symptoms may be located elsewhere where the lung cancer has spread or metastasized.
  • There may be general symptoms of not feeling well due to changes caused in the body by cancer.

Many people with lung cancer do not exhibit any symptoms until the disease has progressed to its advanced stages.

They do not feel pain or other symptoms during the early stages because there are very few nerve endings in the lungs. However, they will feel pain when lung cancer invades the chest wall, ribs, vertebrae, or certain nerves.

Localized lung cancer symptoms are different in each person, and may include:

  • A progressive cough that does not respond to treatment
  • Hoarseness of voice
  • Constant chest pain
  • Shortness of breath or wheezing
  • Frequent lung infections such as bronchitis or pneumonia
  • Haemoptasis – Coughing up blood, rust-colored phlegm, or mucus

Other general cancer symptoms or those due to metastasis to the bones

  • Unexplained weight loss
  • Unexplained loss of appetite
  • Headaches
  • Bone pain or fractures are a sign that lung cancer has metastasized to the bone. The most common bones to which lung cancer spreads include:
    • The spine and the vertebrae in the chest and lower abdomen
    • The pelvis
    • Bones in the arms and thighs
    • Bones in the hands and feet
  • Formation of blood clots. Tumors can also press on blood vessels as they grow and stop or slow down the flow of blood. Whenever blood doesn’t move, clots can precipitate. Some people with lung cancer are more likely to develop blood clots depending on where the tumor is formed. Secondly, cancer increases inflammation in the body, which can increase the risk of blood clot formation.