Everyone has some chance of developing cancer. But some individuals have a higher risk than others. People who smoke, for example, face a greater likelihood of developing cancers of the lung, larynx, pancreas, and bladder than non-smokers. Women who have delayed having children or have never carried a term pregnancy face a greater risk of breast cancer than those who started their families when they were younger or have carried a pregnancy to term.
Family history is also an important risk factor for cancer.
Genes have been identified that contribute to a variety of cancers, including rare forms like sarcomas, as well as common cancers such as breast, ovary, colorectal, and prostate. Depending on their personal and family history, some individuals may decide to have specific genes studied. Genetic information may help some people learn whether they have an increased likelihood of developing certain cancers or whether inherited factors have contributed to their own or a family member's cancer. In some cases, this information may help an individual and his or her physician take steps to detect cancer early and, when possible, prevent it. In others, it may help relieve uncertainties about cancer risk.