Smoking
It is estimated that smoking is the cause of approximately 30% of deaths of cancer. The risk of development of lung cancer is 10 to 20 times higher in smokers that in non-smokers and around 90% of deaths caused by malignant diseases of the lungs is caused by smoking. It has been observed that smoking contributes to the development of tumors in the lungs, genito-urinary system and digestive organs (stomach, large bowel and rectum, pancreas). Passive smoking doubles the risk of lung cancer.
Alcohol
Recently, there have been new proofs of the negative impact of drinking on the development of cancer. People with cirrhosis are also at a higher risk of liver cancer.
Ionizing radiation
Is a causal factor of the development of leukemias, lymphomas and various types of cancer.
UV radiation
Increases the risk of development of malignant melanoma (skin cancer) and other skin tumors (basal cell and squamous cell carcinoma).
Electromagnetic field
No direct relation between the exposure to electromagnetic field and the development of cancer has been established, however, it has been observed that people working with high voltage are at a higher risk of development of gliomas (brain tumors). A connection between a higher risk of cancer and magnetic resonance examination has not been confirmed.
Asbestos
Exposure to asbestos increases the risk of lung, pleura and peritoneum cancers.
Dietetic factors
Causality is probable in the following types of diet influence:
- increased saturated fat intake: breast and colorectal cancer
- high caloric intake: breast, uterine, prostate, colorectal and gallbladder cancer
- increased animal fat intake, especially red meat: breast, uterine and colorectal cancer
- alcohol intake, especially for smokers: head and neck cancer, esophageal cancer and liver cancer
- increased salt, smoked and burnt food intake: esophageal and stomach cancer
- nitrates and nitrite additives: small intestine cancer.
BMI (Body Mass Index) and exercising
A link has been observed between obesity and increased risk of breast cancer, female reproductive organs cancer and prostate cancer. It is supposed that regular exercising reduces the risk of colon cancer and breast cancer.
Chemical factors
We know a huge number of chemical substances with supposed causal relationship to certain oncological diseases (for example, colorants to kidney cancer).
Viruses
It is known that retroviruses have the ability to integrate their genetic information into the genome of the host and according to where the information is integrated, they can prevent the death of damaged cells and cause their increased growth, which can lead to the development of oncological disease. For example, causality has been found between EBV infection (Epstein-Barr virus) and lymphomas, some subtypes of HPV (human papilloma virus) (mainly subtypes 16, 18) and cervical cancer, as well as head and neck cancers, HSV-8 (herpes simplex virus) and Kaposi sarcoma.
Bacteria
It is known that, for example, Helicobacter pylori bacterial infection is connected to increased risk of stomach cancer and stomach lymphomas (of MALT type) in sensitive individuals.
Genetic factors
Many genetic syndromes and individual genetic aberrations are known to increase the risk of development of some oncological diseases and syndromes (e.g. BRCA-1 mutation is connected to an increased risk of breast cancer and ovarian cancer). Klinefelter syndrome is connected to an increased risk of development of primary germ cell tumor of the mediastinum and one subtype of leukemia, so-called acute megakaryocytic leukemia.
Reduced function of the immune system
Reduced function of the immune system is connected to a higher risk of development of oncological diseases, for example lymphomas in patients after organ transplants who regularly take immuno-suppressing drugs or patients with HIV infection or AIDS.
Environmental pollution
Air pollution by emissions, products formed during combustion of fossil fuels, is one of proven carcinogens. Exposure to emissions from diesel engines, benzene or inorganic carcinogens such as asbestos, arsenic and chrome compounds increases the risk of lung cancer in particular. An increase in the number of malignancies can be caused by drinking water contaminated with asbestos fibers, hydrocarbons, pesticides, heavy metals and radioactive isotopes with carcinogenic effects, but also due to pollution with disinfection products, organic solvents, nitrites, nitrates, pesticides.
Lower risk of development of oncological diseases is associated with the implementation of the following measures:
- diet with high fruit content
- diet with high amount of vegetables containing indoles (cabbage, cauliflower, broccoli) – lower risk has been detected in observational trials for colorectal, stomach, breast and cervical cancer
- bioflavonoid intake (contained in red wine and dark chocolate)
- a connection between daily intake of small amounts of acetylsalicylic acid and reduced risk of colorectal cancer has been detected (however, careful in case of those who cannot take acetylsalicylic acid or nonsteroidal antirheumatic agents)
- lower exposure to possible carcinogens (some chemicals – such as dyes, asbestos, smoking)
- regular physical activity
- for at-risk individuals – vaccination against hepatitis B virus, which is a causal factor of liver cancer
- vaccination against HPV (human papilloma virus) which is a causal factor of cervical cancer.
