Menu Close
Find a doctor
Search Button
Cells blue

Different Causes of Cancer

Written by MSD in the Philippines

How many times have you read a headline with these words – “Experts find link between X and cancer”? Smoking, obesity, excessive alcohol drinking, exposure to UV rays, tanning beds, exposure to microwave, cellular sites, power lines, hair dyes, processed foods, red meat and just about anything are supposedly linked to cancer. It can be really confusing, leading to fear.

As a result, people fear cancer more than any other disease. For some, it becomes a mysterious disease because they often hear or read stories that tell how a totally healthy person was suddenly stricken by cancer. These stories elicit strong emotions, bordering on anger, doubt and fear.

They give a sense of helplessness, especially if that allegedly cancer-causing reason is something you are exposed to on a regular basis, like antiperspirants, cellular phones, microwave and the sun’s UV rays.

According to American Cancer Society, cancer is a complex group of diseases with different possible causes. While there are similarities and patterns among cancer patients, each cancer case is unique. There is no single direct link between something and cancer. Most often, cancer develops from various causes. Let’s discuss some of them.


Medical experts agree that cancer is a type of genetic mutation. Why? Cancer begins when genes in a cell become abnormal and the cell starts to grow and divide at a rapid rate.

Some mutations do not have physical and observable effects; others often lead to a disease.

For example, a mutation in the gene of the hemoglobin (red blood cell) causes the disease sickle cell anemia.

Given these conditions, cells become cancer cells when mutations in the gene occur. However, it does not mean that one mutation can lead to cancer immediately. Several pieces of research showed that it takes more than one mutation in a cell for cancer to develop.

Since genes are inherited from the parents, when a person inherited an abnormal copy of a gene, there is already an existing mutation in the body.3 This condition presupposes enough mutations to build up for a cell to become cancer. Imagine that cancer has a foundation in the existing mutation. In this case, cancers that are inherited often manifest earlier in life.3

Nevertheless, if you were born with healthy genes, some of these genes can change and mutate over the years.3 This leads to the second category of the causes of cancer.

Lifestyle and activities

There are lifestyles and activities that can increase the risk of acquiring cancer. Smoking and tobacco have been linked to lung cancer and other types of cancers.5 In the Philippines, 22.7% or 15.9 million adults smoke tobacco, according to a 2015 study by the Global Adult Tobacco Survey by the Philippine Statistics Authority.

It is the leading cause of all lung cancer deaths and chronic obstructive pulmonary disease (COPD). The Centers for Disease Control and Prevention also reported that cigarette smoking harms nearly every organ of the body.

Lung cancer in the Philippines is the most prevalent cause of cancer-related death. In 2020, over 19,000 individuals were recorded to have lung cancer, second only to breast cancer. 8 (

Current smokers or smokers who have quit within the past 15 years are highly encouraged to undergo lung cancer screening procedures in order to find any abnormality in the lungs which may lead to cancer. To know more details about this, you may visit our blog “Why Smokers Should Undergo Cancer Screening: smokers-should-undergo-cancer-screening/

According to Mayo Clinic, here are also some lung cancer symptoms that you should be aware of:

  • A new cough that doesn’t go away
  • Coughing up blood, even a small amount
  • Shortness of breath
  • Chest pain
  • Hoarseness
  • Losing weight without trying
  • Bone pain
  • Headache

Check for these symptoms, but also remember that every medical case is unique and it is important for
you to visit your doctor.

What makes smoking dangerous to your health?

Cigarettes, cigar, and pipe tobacco come from dried tobacco leaves. Additives are combined with the tobacco leaves to make smoking more pleasurable. When these substances are burned, the smoke constitutes thousands of chemicals, including at least 70 known to cause cancer. These cancer-causing chemicals are known as carcinogens. Some of the following chemicals are found in tobacco smoke:

  • ✓ Arsenic
  • ✓ Ammonia
  • ✓ Benzene
  • ✓ Carbon monoxide
  • ✓ Formaldehyde
  • ✓ Hydrogen cyanide
  • ✓ Lead
  • ✓ Nicotine
  • ✓ Nitrosamines
  • ✓ Polycyclic aromatic hydrocarbons (PAHs)
  • ✓ Radioactive elements like uranium

Did you know that even if you do not smoke, exposure to tobacco smoke can cause cancer?

American Cancer Society described this as secondhand smoke, involuntary smoking or passive smoking. Non-smokers who breathe in secondhand smoke take in the same nicotine and toxic chemicals.

Secondhand smoke has been associated with adult cancers of the larynx, pharynx, nasal sinuses, brain, bladder, rectum, and stomach. Experts also noted that children whose parents smoke are more likely to get sick often, develop lung infection, and ear infection.

Diet and physical activity

Excess body weight may increase cancer risk. If a person has excess body fat, it will affect the following

  • ✓ Immune system function and inflammation
  • ✓ Increase levels of insulin and estrogen
  • ✓ Factors that regulate cell growth, like insulin-like growth factor

In addition to this, too much belly fat, regardless of body weight, can increase the risk of colon and rectal cancer.

Excessive exposure to UV rays

UV or ultraviolet rays often comes from the sun and man-made sources like tanning beds.

According to the World Health Organization, getting anywhere from 5 to 15 minutes of sunlight on your arms, hands, and face 2-3 times a week is enough to enjoy the vitamin D-boosting benefits of the sun. However, excessive exposure to UV rays can damage the skin and cause any of the following skin problems:

  • ✓ Benign tumors
  • ✓ Discolored areas of the skin, called mottled pigmentation
  • ✓ Elastosis — the destruction of the elastic and collagen tissue that cause lines, wrinkles and sagging skin
  • ✓ Fine and coarse wrinkles
  • ✓ Freckles
  • ✓ Pre-cancerous and cancerous skin lesions like melanoma
  • ✓ Sallowness — a yellow discoloration of the skin
  • ✓ Telangiectasias — the dilation of small blood vessels under the skin

How can you protect yourself?

Many cancers are preventable. For example, if you avoid smoking, excessive alcohol drinking and keep a healthy and balanced lifestyle, you are preparing your body by boosting your immune system and keeping your overall health in tiptop shape.

Early screening also helps prevent cancer or address any possible occurrence of cancer in the body. If you know a gene-related health issue that runs in the family, get an accurate diagnosis by asking your doctor for early testing and laboratory tests. If your prior lifestyle includes smoking, alcohol drinking, excessive exposure to UV rays and radiation, don’t take any chances. Get yourself checked by your doctor.

The age-old adage “Prevention is better than cure” remains as your first line of defense against cancer and other types of diseases.


1. “What Causes Cancer?”. American Cancer Society.

html. Accessed November 5, 2018.

2. “Known and Probable Human Carcinogens.” American Cancer Society. Accessed November 5, 2018.

3. “Changes in Genes.” American Cancer Society. Accessed November 5, 2018.

4. “Causes of Cancer and Reducing Your Risk”. Cancer Research UK. Accessed November 5, 2018.

5. “Health Risks of Smoking Tobacco.” American Cancer Society. Accessed November 5, 2018.

6. “Global Adult Tobacco Survey: Executive Summary 2015.” Philippine Statistics Authority. Accessed May 3, 2019.

7. “Smoking and Tobacco Use.” Centers for Disease Control and Prevention. Accessed November 5, 2018.

8. “Harmful Chemicals in Tobacco Products.” American Cancer Society. Accessed November 5, 2018.

9. “Health Risks of Secondhand Smoke”. American Cancer Society.

Accessed November 5, 2018.

10. “Diet and Physical Activity: What’s the Cancer Connection?”. American Cancer Society. Accessed November 5, 2018.

11. “Does Body Weight Affect Cancer Risk?”. American Cancer Society. Accessed November 5, 2018.

12. “Ultraviolet (UV) Radiation”. American Cancer Society. Accessed November 5, 2018.

13. “The Known Health Effects of UV”. World Health Organization. Accessed November 5, 2018.

14. “Can Cancer Be Prevented?” Cancer Research UK. Accessed November 5, 2018.

15. “Understanding Genetic Testing for Cancer.” American Cancer Society. Accessed November 5, 2018.

Share This

Copy Link to Clipboard