Cancer is characterized by the presence of abnormal, malignant cells in the body. Cancer develops when the DNA within cells becomes damaged and it is not repaired by the body.

Scientists continue to study the reasons for the development of cancer. In many cases, the risk factors for cancer cannot be controlled. Age, for instance, is considered a risk factor because the chances of cancer developing increase as people grow older. Family medical history also plays a role in whether a person has a higher likelihood of developing some cancers.

Although some risk factors are unavoidable, other factors can be controlled. There are substances that have been clearly linked with cancer. These substances are known as carcinogens and use or exposure to carcinogens can increase the risk for certain cancers. Smoking, for instance, clearly causes lung cancer and many head and neck cancers.

Simple lifestyle modifications and precautions, such as not smoking, limiting alcohol consumption and limiting exposure to ultraviolet rays, can help reduce the risk of some cancers. In addition to reducing lifestyle risks, cancer can be prevented through early detection and risk assessment. Regular screenings have dramatically improved the survival rates for many cancers, such as breast cancer, cervical cancer and prostate cancer.