what causes cancer

What causes cancer:Overview

what causes cancer? cancer is caused by accumulated damage to genes. Such changes may be due to chance or to exposure to a cancer causing substance.
The substances that cause cancer are called carcinogens. A carcinogen may be a chemical substance, such as certain molecules in tobacco smoke. The cause of cancer may be environmental agents, viral or genetic factors.

We should bear in mind, though, that in the majority of cancer cases we cannot attribute the disease to a single cause.

We can roughly divide cancer risk factors into the following groups:



  1. biological or internal factors, such as age, gender, inherited genetic defects and skin type

  2. environmental exposure, for instance to radon and UV radiation, and fine particulate matter

  3. occupational risk factors, including carcinogens such as many chemicals, radioactive materials and asbestos

  4. lifestyle-related factors.

Lifestyle-related factors that cause cancer include:



  • tobacco

  • alcohol

  • UV radiation in sunlight

  • some food-related factors, such as nitrites and poly aromatic hydrocarbons generated by barbecuing food).


What causes cancer?


Lifestyles can prevent cancer


Cancer causing factors related to work and living environments include:



  • asbestos fibres

  • tar and pitch

  • polynuclear hydrocarbons (e.g. benzopyrene)

  • Some metal compounds

  • Some plastic chemicals (e.g. Vinyl chloride)


Bacteria and viruses can cause cancer:



  • Helicobacter pylori (H. pylori, which causes gastritis)

  • HBV, HCV (hepatitis viruses that cause hepatitis)

  • HPV (human papilloma virus, papilloma virus, which causes changes eg. Cervical cells)

  • EBV (Epstein-Barr virus, the herpes virus that causes inflammation of the throat lymphoid)

Radiation can cause cancer:



  • ionising radiation (e.g. X-ray radiation, soil radon)

  • non-ionised radiation (the sun’s ultraviolet radiation)

Some drugs may increase the risk of cancer:



  • certain antineoplastic agents

  • certain hormones

  • medicines that cause immune deficiency

In 5 – 10 per cent of breast cancer genetic predisposition plays an important role in the emergence of the disease.



Cancer risk prevention tips:


Concerned about cancer prevention? Take charge by making changes such as eating a healthy diet and getting regular screenings.


You've probably heard conflicting reports about cancer prevention. Sometimes a specific cancer-prevention tip recommended in one study is advised against in another.

Often, what's known about cancer prevention is still evolving. However, it's well-accepted that your chances of developing cancer are affected by the lifestyle choices you make.

So if you're interested in preventing cancer, take comfort in the fact that simple lifestyle changes can make a difference. Consider these cancer-prevention tips.

1. Don't use tobacco



Using any type of tobacco puts you on a collision course with cancer. Smoking has been linked to various types of cancer — including cancer of the lung, mouth, throat, larynx, pancreas, bladder, cervix and kidney. Chewing tobacco has been linked to cancer of the oral cavity and pancreas. Even if you don't use tobacco, exposure to secondhand smoke might increase your risk of lung cancer.

Avoiding tobacco — or deciding to stop using it — is an important part of cancer prevention. If you need help quitting tobacco, ask your doctor about stop-smoking products and other strategies for quitting.

2. Eat a healthy diet



Although making healthy selections at the grocery store and at mealtime can't guarantee cancer prevention, it might reduce your risk. Consider these guidelines:

  • Eat plenty of fruits and vegetables. Base your diet on fruits, vegetables and other foods from plant sources — such as whole grains and beans.

  • Avoid obesity. Eat lighter and leaner by choosing fewer high-calorie foods, including refined sugars and fat from animal sources.

  • If you choose to drink alcohol, do so only in moderationThe risk of various types of cancer — including cancer of the breast, colon, lung, kidney and liver — increases with the amount of alcohol you drink and the length of time you've been drinking regularly.

  • Limit processed meats. A report from the International Agency for Research on Cancer, the cancer agency of the World Health Organization, concluded that eating large amounts of processed meat can slightly increase the risk of certain types of cancer.


In addition, women who eat a Mediterranean diet supplemented with extra-virgin olive oil and mixed nuts might have a reduced risk of breast cancer. The Mediterranean diet focuses mostly on plant-based foods, such as fruits and vegetables, whole grains, legumes, and nuts. People who follow the Mediterranean diet choose healthy fats, such as olive oil, over butter and fish instead of red meat.

3. Maintain a healthy weight and be physically active



Maintaining a healthy weight might lower the risk of various types of cancer, including cancer of the breast, prostate, lung, colon and kidney.

Physical activity counts, too. In addition to helping you control your weight, physical activity on its own might lower the risk of breast cancer and colon cancer.

Adults who participate in any amount of physical activity gain some health benefits. But for substantial health benefits, strive to get at least 150 minutes a week of moderate aerobic activity or 75 minutes a week of vigorous aerobic activity. You can also do a combination of moderate and vigorous activity. As a general goal, include at least 30 minutes of physical activity in your daily routine — and if you can do more, even better.

4. Protect yourself from the sun



Skin cancer is one of the most common kinds of cancer — and one of the most preventable. Try these tips:

  • Avoid midday sun. Stay out of the sun between 10 a.m. and 4 p.m., when the sun's rays are strongest.

  • Stay in the shade. When you're outdoors, stay in the shade as much as possible. Sunglasses and a broad-brimmed hat help, too.

  • Cover exposed areas. Wear tightly woven, loose fitting clothing that covers as much of your skin as possible. Opt for bright or dark colors, which reflect more ultraviolet radiation than do pastels or bleached cotton.

  • Don't skimp on sunscreen. Use a broad-spectrum sunscreen with an SPF of at least 30, even on cloudy days. Apply sunscreen generously, and reapply every two hours — or more often if you're swimming or perspiring.

  • Avoid tanning beds and sunlamps. These are just as damaging as natural sunlight.


5. Get vaccinated



Cancer prevention includes protection from certain viral infections. Talk to your doctor about vaccination against:

  • Hepatitis B. Hepatitis B can increase the risk of developing liver cancer. The hepatitis B vaccine is recommended for certain adults at high risk — such as adults who are sexually active but not in a mutually monogamous relationship, people with sexually transmitted infections, people who use intravenous drugs, men who have sex with men, and health care or public safety workers who might be exposed to infected blood or body fluids.

  • Human papillomavirus (HPV). HPV is a sexually transmitted virus that can lead to cervical and other genital cancers as well as squamous cell cancers of the head and neck. The HPV vaccine is recommended for girls and boys ages 11 and 12. The U.S. Food and Drug Administration recently approved the use of vaccine Gardasil 9 for males and females ages 9 to 45.


6. Avoid risky behaviors



Another effective cancer prevention tactic is to avoid risky behaviors that can lead to infections that, in turn, might increase the risk of cancer. For example:

  • Practice safe sex. Limit your number of sexual partners and use a condom when you have sex. The more sexual partners you have in your lifetime, the more likely you are to contract a sexually transmitted infection — such as HIV or HPV. People who have HIV or AIDS have a higher risk of cancer of the anus, liver and lung. HPV is most often associated with cervical cancer, but it might also increase the risk of cancer of the anus, penis, throat, vulva and vagina.

  • Don't share needles. Sharing needles with people who use intravenous drugs can lead to HIV, as well as hepatitis B and hepatitis C — which can increase the risk of liver cancer. If you're concerned about drug misuse or addiction, seek professional help.


7. Get regular medical care


Regular self-exams and screenings for various types of cancers — such as cancer of the skin, colon, cervix and breast — can increase your chances of discovering cancer early, when treatment is most likely to be successful. Ask your doctor about the best cancer screening schedule for you.what causes cancer

Summary


Cancer treatment is not yet certain.It has no complete known cause, the causes mentioned above are the strongest suspects after a good research by great lab and clinical people.So we strongly take them as the causes. Most of the cancer patients were found to have been exposed or engaged in one of the above risks. therefore it is good to avoid such risks.What causes cancer