Cancer Causes & Risk Factors Top Causes and Risk Factors for Developing Cancer By Lisa Fayed Updated February 15, 2018 Share Pin Email Print Jonathan Pow/Getty Images More in Cancer Causes & Risk Factors Symptoms Diagnosis Treatment Living With Support & Coping Prevention Bladder Cancer Brain Tumors Breast Cancer Cervical Cancer Childhood Cancer Colon Cancer Gastric Cancer Head & Neck Cancer Liver Cancer Leukemia Lymphoma Lung Cancer Ovarian Cancer Pancreatic Cancer Prostate Cancer Skin Cancer Testicular Cancer Thyroid Cancer More Cancer Types View All What are the most important causes and risk factors for developing cancer? Most people don't realize that cancer is preventable in many cases. Learning what causes cancer and what the risk factors are is the first step in cancer prevention. Many cancer risk factors can be avoided on the one hand, or changed in another, to reduce your risk.Causes and Risk Factors for CancerAs with many things in life, our perceptions of what is a risk for cancer, and what is really a risk don't always coincide. Can wearing deodorant cause breast cancer? Do underwire bras cause cancer? Unfortunately, many of these discussions go on while people are innocently exposed to known causes of cancer.TobaccoAccording to the National Cancer Institute, smoking causes 30% of all cancer deaths in the U.S. and is responsible for 87% of cases of lung cancer. Not only does it affect the lungs, but smoking increases the risk of many cancers. Quitting smoking immediately decreases your risk factor for cancer.Physical Activity/ExerciseExercising at least 30 minutes a day, 5 days a week greatly reduces your cancer risk. Exercise like yoga, aerobics, walking, and running are great activities to lower your risk. Not only is physical activity important in preventing cancer on its own, but it reduces the risk of obesity - and obesity is a leading cause of cancer. You don't need to run marathons. It's been found that even light exercise -- such as working in the garden a few days a week - reduces the risk of lung cancer among others. Your GenesGenetics can play a big role in the development of some cancers. If you have a family history of cancer, such as breast cancer, taking extra precautions is vital. When cancer is genetic, a mutated gene may have been passed down. Genetic tests are available for some hereditary cancers. Keep in mind that if you have a family history of cancer, it does not mean you will develop it. You only have a greater chance of developing it (a genetic predisposition.)Environmental ExposuresYour surroundings can raise your risk of developing cancer. Exposure to asbestos, a group of minerals found in housing and industrial building materials can cause a variety of medical problems, such as mesothelioma - a cancer of the lung lining. Studies have shown that people who are exposed to high amount of benzene are at risk for cancer. Benzene is a chemical found in gasoline, smoking, and pollution. There are many other substances in our environment that could put you at risk. Be careful with chemicals in your home, and always take time on the job to read the information provided about the chemicals you work with.Unsafe SexPracticing unsafe sex can increase your risk of developing a virus called human papillomavirus - HPV. HPV is a group of over 100 viruses. Not all strains of HPV cause cancer, but some strains increase your risk for cervical, anal, vulvar and vaginal cancer. Recent studies suggest that HPV also plays an important role in many head and neck cancers, and research is ongoing looking at its possible role in other cancers as well.Sun ExposureSkin cancer may be caused by excess exposure to UV rays from the sun. Many people don't realize that a sunburn -- even a tan -- is actually the result of skin damage caused by the sun. Many cases of skin cancer can be prevented through a little planning. Wearing sunscreen can help, but practice safe sun exposure as well. Avoid direct sunlight mid-day (from 10 am to 2 pm,) sit under an umbrella, wear protective clothing, and don't forget sunglasses to protect your eyes. One form of skin cancer - melanoma - has a tendency to affect the eyes. A discussion of sun exposure isn't complete without bringing up vitamin D. Vitamin D is a vitamin which acts more like a hormone in the body, and is manufactured in our skin via sun exposure. It's been found in recent years that a vitamin D deficiency - something that affects over half of U.S. citizens - is a risk factor for many types of cancer. That doesn't mean you should throw away the sunscreen, especially since a simple blood test can tell you if you are deficient or not. Ask to have a level checked at your next physical exam.Sources:National Cancer Institute. Risk Factors for Cancer. Updated 12/23/15. http://www.cancer.gov/about-cancer/causes-prevention/risk Continue Reading