The impact of cancer A. U. S. probabilites 1. 1 out of every 4 people alive today will probably get cancer 2. More than 1 out of 5 people will be killed by cancer 3. Diseases other than cancer can often be cured now which couldn't be cured in 1900. Curing infectious diseases allows people to live longer. Even for a given age group cancer is more frequent now than in 1900.
Epidemiology is an approach to study of diseases such as cancer.
An epidemiological study uses statistics to look for correlations. So in a way these studies are sad, since you can't do anything to help the people who have already gotten cancer. But at least you can get information that can help other people in the future. In 1775, study of chimney sweeps led to coal dust being suspected as being a cause of cancer of the penis and scrotum. Protective clothing and frequent washing lowered the incidence of cancer.