Judy Chase, Pharm. There is progress in the fight against cancer. For instance, mortality rates have recently decreased for colorectal, lung, breast and prostate cancers in individuals under age 65 years. The science of epidemiology studies the variations in disease frequencies among human population groups and the factors influencing these variations. Cancer incidence is defined as the number of newly diagnosed cases of cancer in a specified period of time in a defined population.
Demographic information includes factors such as age, gender, marital status and place of residence.
Medical data include onset of illness, location, stage of tumor, treatment and survival over time. This information helps researchers to describe the current cancer problem in terms of geographic distribution, age and race of patients and increase or decrease in specific types of cancer. Many factors need to be considered when analyzing incidence data. For example, there has been a slight but steady increase in the overall cancer incidence over the past decade. However, this information does not necessarily mean that cancer is on the rise.