by admin at Monday, April 06, 2009 in Cancer, Health Care
Tags:  cancer, cancer-free, chain smoker, drinking too much alcohol, lung cancer

Cancer: Main Causes and Risk Factors

To some extent, a cancer can be prevented. Several causes and risk factors for cancer were identified so far.

Smoking

It is the tar in the smoke that causes lung cancer, cancer in the throat (laryngeal cancer), and cancer in the stomach (gastric carcinoma), and bladder cancer.

Second-hand smoking also represent cancer risk.

Tobacco, smokeless.

Alcohol

Alcohol, among other, causes pancreatic, liver, colon and breast cancer (3).

Low-Fiber Diet

Low fiber diet may cause constipation, thus prolonging contact time of harmful substances in the food with the intestinal wall, and increasing the risk for colo-rectal cancer.

Meat

High intake of red (beef, pork, veal and lamb), or processed meat (salami, hamburgers..), over a long period of time increases the risk for colo-rectal cancer (3).

Other Foods (1)

• Areca nut
• Salted fish (Chinese-style)

Obesity (3)

Obesity and sedentary life increase risk of cancer.

Sunburn

Heavy (blistering) sunburn increases the risk for skin cancer (basal and squamous cell carcinoma, and melanoma) at any later time in life. Any exposure to ultraviolet UV-B and UV-A rays (sun, tanning saloons) theoretically increases risk for skin cancer.

Melanoma (besides on the head and arms) often appears on the skin areas that were not regularly exposed to the sun but were affected by a single episode of sunburn. Details of skin cancer risk factors.

Microbes

• Aflatoxins, produced by some fungi
• Epstein-Barr virus – Burkit’s lymphoma (rare)
• Helicobacter pylori – stomach cancer
• Hepatitis B and C virus – liver cancer
• HIV (AIDS)
• Human papillomavirus (HPV) types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 66 represents a risk for cervical cancer
• Human T-cell lymphotropic virus (HTLV) type I
• Schistosoma haematobium

Asbestos

Asbestos is a well known cause of mesothelioma. Several years/decades of exposure are usually needed for cancer to develop.

Dioxin

Dioxin appears in the air and water mainly after waste combustion, and even after big forest fires (2).

Medications (1)

• 8-Methoxypsoralen (Methoxsalen) plus UV-A radiation
• Cyclosporine
• Estrogen-progestogen menopausal therapy and oral contraceptives increase risk for the breast cancer (4)
• MOPP and other combined chemotherapy including alkylating agents
• Phenacetin
• Tamoxifen (may reduces the risk of contralateral breast cancer though)

Radioactive Substances (1)

• Neutrons
• Plutonium-239
• Radioiodines, like iodine-131, from atomic reactor accidents and nuclear weapons detonation
• Radionuclides, a- and  b-particle-emitting, internally deposited
• Radium-224, -226, -228
• Radon-222
• X- and Gamma (g)-Radiation

Other Chemicals (1)

• Arsenic
• Benzene
• Beryllium
• Cadmium
• Chromium
• Formaldehyde
• Mustard gas (Sulfur mustard)
• Nickel
• Silica particles, when inhaled
• Talc containing asbestiform fibres
• Vinyl chloride
• Household combustion of coal, indoor emissions from
• Mineral oils
• Plants containing aristolochic acid
• Shale-oils
• Soots
• Wood dust

Work Environment (1)

People working in the following environments are at increased risk to develop a cancer:

• Aluminium production
• Arsenic in drinking-water
• Boot and shoe manufacture and repair
• Chimney sweeping
• Coal gasification
• Coke production
• Furniture and cabinet making
• Iron and steel founding
• Magenta production
• Painting
• Paving and roofing with coal-tar pitch
• Rubber industry
• Sulfuric acid production

Conclusion

Avoiding smoking, excessive drinking, excessive sun exposure (or, if not possible, using sunscreens with sun-protecting factor 15+ instead), red/processed meat, obesity, and sedentary life are main measures to prevent cancer.

Avoiding of long term exposure to cancerogenes substances should be also considered.

References:

1. Substances, carcinogenic to humans (monographs.iarc.fr)
2. Dioxin is carcinogenic (ejnet.org)
3. Risk factors of common cancers (yourdiseaserisk.wustl.edu)
4. Risk factors of common cancers (II) (yourdiseaserisk.wustl.edu)

Article reviewed and edited by Jan Modric on April 07, 2009