Some cancer risk may be related to diet. Cancers develop slowly in people. They usually appear five to 40 years after exposure to a carcinogen. For example, cancer of the lung may not occur until 30 years after a person starts smoking. This long latency period is one of the reasons it is difficult to determine what causes cancer in humans.
Cancer is a very common disease.
One in three people will be diagnosed with cancer at some time in their life. Eventually, cancer occurs in three out of every four families. In New York, nearly one in four deaths is due to cancer. Cancer occurs at all ages, but most often in middle-aged and older people. The number of people diagnosed with cancer has increased over the past 40 years.