If, for example, a family history shows that many female family members in the past have been particularly vulnerable to breast or ovarian cancer, current generations need to be particularly diligent about regular screening examinations for these diseases. If your family has a particularly high incidence of cancer, especially if cancer develops frequently in family members under 45 years of age or if individuals develop multiple different cancers, a cancer-risk evaluation may be worthwhile. Most universities have designated comprehensive cancer centers you can contact. As more is learned about cancer genetics, it may someday be possible to manipulate genes with genetic engineering that blocks or removes cancer-causing genes or, alternatively, implants genes that promote cancer resistance. Radiation, chemical substances in the air and diet, certain viral infections, and vitamin deficiencies can all damage genes and result in cancer.
Research continually expands our understanding of cancer's causes and development.
According to the American Cancer Society, one out of every three cancer deaths in the United States today is directly linked to tobacco. Since smoking and chewing tobacco also contribute to 225,000 heart attack deaths a year, this substance is by far the leading cause of preventable death. Besides its association with lung cancer, smoking is also a major factor in causing cancers of the mouth, pharynx, larynx, esophagus, pancreas, and bladder. The complete elimination of smoking would save more than 160,000 lives per year in the United States. Although definitive evidence linking diet to cancer has not been established, research has focused on these possibilities.