A risk factor is anything that increases a person’s chance of developing a specific disease. Cancer is not a single disease but a group of more than 100 different diseases. With so many types of cancer affecting various parts of the body, the risk factors for developing cancer vary greatly depending on the specific type.

Risk factors for certain cancers can be related to environmental factors, genetic predispositions,  compromised immune systems or viral infections. Other cancers have no known causes.

Most cancers have more than one risk factor. These can include things such as age, race, sex, family history, diet, lifestyle factors, exposure to chemicals, radiation and socioeconomic status. While some risk factors are within a person’s control, such as lifestyle habits, other factors, including family history and genetics, cannot be controlled.

Having one or more risk factors for a type of cancer means an individual is more likely to develop that disease. It does not mean the person will absolutely develop the disease. In some cases, people with known risk factors never have cancer in their lifetime. In other cases, cancer occurs in seemingly healthy people with no risk factors. The relationship of risk factors to disease is never completely certain because after a  person develops cancer, there is no way to prove a risk factor was responsible for causing the disease. However, there are some statistical likelihoods, such as lung cancer developing in someone who smokes heavily.