Public Health Surveillance Glossary

Age-adjustment. Age is the most important risk factor for the incidence of most cancers. Cancer rates derived from populations that differ in underlying age structure are not comparable. Therefore, age-adjustment is a statistical technique that allows for the comparison of rates among populations having different age distributions by weighting the age-specific rates in each population to one standard population.

Ascertainment. Ascertainment refers to the quality assurance procedures Maryland Cancer Registry staff use for insuring completeness of cancer cases in the registry database. These activities include a review of disease indices from all reporting hospitals to identify possible missed cases, a random sample of records from reporting facilities, and review of death certificate data to identify cancer cases not previously reported.

Avoidable Health Event. Being hospitalized for a preventable condition - an indicator of limited access to primary care.

Cancer. A disease characterized by the uncontrolled, abnormal growth of cells in different parts of the body that can spread to other parts of the body.

Chemoprevention. Chemoprevention is the use of drugs, vitamins, or other agents to try to reduce the risk of cancer or to delay the development or recurrence of cancer.

Etiology. The study of the causes of disease.

Incidence. The rate of new cases of a given cancer or other event during a defined period, usually one year.

Incidence rate. Incidence rate is the number of new cases during a specific period (usually one year) divided by the population at risk, standardized to a population of 100,000.

Invasive cancer. A stage of cancer in which cancer cells have spread to healthy tissue adjacent to the tumor. It may still be considered localized if it has not spread to other parts of the body.

Lifetime risk. The probability of developing or dying of cancer across a full lifetime.

Leading Indicator. A set of indicators available to provide reliable information to policymakers and the public about the factors key to their health prospects and health goals. Example: cancer screening rates in screen-recommended population.

Morbidity. State of ill-health produced by a disease.

Mortality. Number of deaths that occurred during a defined time, for example, one year.

Mortality rate. Mortality rate is the number of deaths for a given period divided by the population at risk per 100,000 population.

Prevalence. The number of persons with a disease who are alive on a certain date.

Primary prevention. Primary prevention is preventing cancer before it has developed such as through avoiding carcinogens (e.g., avoiding tobacco, promoting a healthy lifestyle through exercise and diet) or preventing the harmful effects of carcinogens (e.g., using sunscreen), and detecting and removing precancerous lesions (e.g., removing polyps in the colon)

Rate. A rate is an estimate of the burden of a given disease in a defined population in a specified period of time. A crude rate is calculated by dividing the number of cases (events) by the population at risk during a given time period. Cancer incidence and mortality rates are usually presented per 100,000 population during a given period.

Screening. Screening is checking for disease when there are no symptoms resulting in detection of malignancies in situ or in an early stage.

Sentinel event. A preventable disease, disability, untimely death or other indicator that serves as a warning signal that the quality of preventive and/or therapeutic medical care may need to be improved.

Stage at diagnosis. The extent to which the cancer has spread from the organ of origin at the time of diagnosis.

In situ. The cancerous cells have not invaded the tissue basement membrane; that is the cells are still contained. In situ cancers are not considered malignant (with the exception of bladder cancers) and are not included in incidence rate calculations.

Localized. The tumor is confined to the organ of origin.

Regional. The tumor has spread to adjacent organs or tissue. Regional lymph nodes may also be involved.

Distant. The tumor has spread beyond the adjacent organs or tissues. Distant lymph nodes, organs and/or tissues may also be involved.

Unstaged. Stage of disease at diagnosis was unable to be classified (often due to insufficient information) or was not reported to the cancer registry.

Survival. The proportion of patients alive at a given time after the diagnosis of cancer. Five- year survival is often used.

 

Epidemiological Dictionaries

Clinical Epidemiology & Evidence-Based Medicine Glossary​