**Epidemiology**

The population at risk is the part of the population that is likely to develop a specific cancer. It is defined based on demographic data, eg place of residence, sex, age, etc .

Crude incidence is the number of new cases of cancer occurring in a given period of usually one year at a specified population (100,000 people).

Crude death rate is the number of cancer deaths that occur in a given period of usually one year at a specified population (100,000 people).

Standardized incidence and mortality by age (ASR) is that there incidence and mortality in a population if it had a standard age structure. The most widely used standard population is the world standard population and the indicators are termed age standardized incidence and mortality.

The cumulative rate is the probability or risk of individuals developing the disease during a specified period.

Cancer is expressed as the number of newborns (100 or 1000) that is expected to develop a particular cancer before age 65 years (or 70 years or 75 years) if the rate as the current cancer incidence observed.

The prevalence in epidemiology, the proportion of the population proved to have a state (usually a disease or a risk factor like smoking and seat belt usage). It is obtained by comparing the number of people found to have the disease that the total number of people surveyed and is usually expressed as a fraction, as a percentage or the number of cases to 10,000 people or 100,000 people.

**Tabels No 1: Incidence and mortality by cancer in Mehedinti county during1990-2014**