Cancer is a complex and multifaceted disease, so there’s no single way to treat it, prevent it, or predict its development. There are thousands of variables, including genetic factors and environmental conditions, that could feasibly increase your risk of developing cancer. 

To the average consumer, this is troubling. Any medication you take or product you use could somehow increase your chances of developing one of the most dangerous diseases known to man. Of course, some of these are more common and more severe than others; for example, it’s been recently discovered that personal use of talcum powder, a commonly manufactured substance, has been linked to ovarian cancer and other complications. This puts talcum powder users in jeopardy, but compared to other sources of cancer, it’s not nearly as widespread. 

So what are the most common causes of cancer? 

Genetic Factors

The majority of cancers aren’t directly linked to specific genes, but there are some cancers that run in the family. Genetically linked cancers tend to develop at younger ages than usual, and tend to affect one specific area of the body—even in the sex not usually affected, such as breast cancer in men. You can surmise a genetic history of cancer in your family if people in multiple generations have been affected by the same types of cancer, if your family has a higher-than-average cancer diagnosis rate, or if there are rare developments, like childhood cancer or cancer occurring in both units of a paired organ (like both eyes or kidneys). There is no way to reduce your genetic risk. 

Smoking and Tobacco Use

Despite decades of knowledge that smoking and tobacco use are inherently unhealthy (and in multiple ways), they remain somewhat popular products. Roughly 38 million people still smoke cigarettes either every day or some days, and those people are at increased risk of cancer development. For people who smoke cigarettes, lung cancer is extremely common later in life. For those who use tobacco products like chewing tobacco, oral cancers are common. It’s best to avoid these products altogether. 

Diet and Physical Activity

The quality of your diet and your level of physical activity may also be tied to your cancer risk. People who get regular vigorous exercise, people who maintain a healthy weight, and people who have a diet rich in vegetables, fruits, and lean proteins tend to develop cancer at a much lower rate compared to others. Fast food, junk food, sweets, and alcohol can increase your cancer risk if you’re consuming a lot of them. The same is true of a sedentary lifestyle. Fortunately, these factors are largely in your control; work on improving your diet and moving as much as possible on a regular basis. 

Exposure to Sunlight and/or Radiation 

Any type of radiation, including the UV radiation emitted by the sun, can increase your risk of cancer. Radiation causes cell damage, which can sometimes trigger a mutation; if that mutation is malignant, it turns into a problem, so the more radiation you’re exposed to, the higher your chances of this occurring. Most people don’t have to worry much about ionizing radiation from X-rays, gamma rays, or particles from nuclear reactions, but they do have to worry about the sun. Wear clothing that sufficiently covers you when outside, and always apply sunscreen to exposed skin. 

Viruses and Other Infections 

There’s also evidence that some types of infections could increase your risk of cancer, and in different ways. For example, certain viruses affect how your cells grow, and could cause some cells to grow out of control, and some infections can result in long-term inflammation, which can cause affected cells and immune cells to undergo massive changes. 

Carcinogenic Substances

A substance is known as “carcinogenic” if it has been shown to facilitate the development of cancer. There are literally hundreds of carcinogenic and possibly carcinogenic materials, which is why we’ve grouped them all in this single category. You probably already know a few of these off-hand; for example, one of the reasons smoking causes cancer is because it contains multiple carcinogenic compounds. Asbestos, famed for its ties to cancer, is also a carcinogen. Some mild carcinogens, like processed meat and alcohol, are fairly common, while most dangerous carcinogens, like formaldehyde, are rare. Make sure you do your research before exposing yourself to something new, or working in a new environment. 

There’s no way to completely avoid cancer. It’s a disease that comes in many forms and arises under many independent conditions. In fact, if you live long enough, it’s a near certainty that you’ll eventually develop the disease. All you can do is avoid some of the most common bad habits and environmental causes of cancer to reduce your risk and prolong your lifespan as long as you can.