What causes Cancer

October 2017

The type of cancer you can get is dependent on where in the body the abnormal cell reproduction begins.

This could be your skin in the form of a melanoma, or start in the lung for example.

There are over 200 types of cancer and there is not one single cause; it is said to be multifactorial:


Most cancer types are more common as we age.

Less than 1% of cancers are diagnosed in children below 14 years of age whereas 64% of all new cancer diagnoses affect people over the age of 65 years.

This may because some cancers take longer to grow, or that an older person has had more time to be subjected to any of the other risk factors.


Some cancers are more common depending on your gender.

In men, Prostate cancer is by far the most prevalent causing approximately 25% of cases. This is followed by lung cancer and then bowel cancer in third.

The most common cancer in females is breast cancer which accounts for nearly a third of cases. Bowel cancer comes second, followed by bowel cancer.


Some cancers are more common within families; 5 to 10% of cancers may have a genetic predisposition.

If you have more than one family member affected, you may have a higher risk of developing this cancer, and so may be referred by your GP for screening. This is the case with breast and colon cancer in the UK for example.

Genetic testing can help to locate abnormalities in your DNA which can be passed onto your children. Your GP may refer you to a hospital specialist for further investigation in your DNA if necessary.

Other risk factors

  • Carcinogens: Exposure to certain chemicals can cause normal cells to mutate into the abnormal cells that cause cancer. Lung cancer is cause by the most common carcinogen; Tobacco smoke.
  • Radiation: Cancer can be caused by exposure to excess radiation e.g. tanning beds.
  • Infectious Diseases: Some diseases or viruses are linked with cancer. For example, Human Papilloma Virus (HPV) is responsible for 95% of cervical cancer, and hepatitis B and C are risk factors for liver cancer.
  • Hormones: Change in levels of hormones can increase the risk of cancer. Breast cancer is more common in postmenopausal women when there are changes in their oestrogen level.
  • Low immunity: There is more risk of cancer in those patients who have a reduced immune response e.g. patients who are HIV positive.
  • Unhealthy lifestyle: There is evidence that people who have a healthy diet and regularly exercise have a lower risk of developing cancer.

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Latest update on September 21, 2014 at 04:45 PM by Ambucias.
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