WISH Cancer Module Definitions

Cancer Incidence

The number of new cancer cases that occur during a specified period for a population at risk for developing the disease, expressed as number of cases or as a rate, usually per 100,000 persons.

Cancer Mortality

Deaths from cancer that occur during a specified period of time for a particular population, expressed as number of deaths or as a rate, usually per 100,000 persons.

Cause of Death

The underlying cause of death is the disease or injury that initiated the train of events leading directly to death. Under international rules for selecting underlying cause from the reported conditions, every death is attributed to one underlying cause based on information reported on the death certificate.

Crude Rate

A crude incidence or mortality rate is the ratio of the number of people in which the disease (incidence) or death (mortality) occurred in a specified time period to the size of the population who may experience that event during the same time period. A crude rate is unadjusted.

Age-Adjusted Rate

This is an incidence or mortality rate adjusted to account for different age distributions between populations. In WISH, rates are age-adjusted using the 2000 U.S. standard population. This is the direct method of calculating rates, in which the age-specific crude rates in the Wisconsin population are weighted by the proportionate age distribution of the standard U.S. population. Age-adjusted rates can be compared only when the same standard population and adjustment method are used in the calculations. Most cancer incidence and death rates in national publications are age-adjusted.

Confidence Interval

A 95 percent confidence interval is commonly reported with rates and contains the true value 95 percent of the time. The range between the lower and upper confidence interval includes with 95 percent probability the "true" rate. The larger the confidence interval, the less precise the estimate.

Statistically Significant

This term describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone 95% of the time. In WISH Cancer Module results, a difference between two rates can be termed "statistically significant" when the confidence intervals for the two rates do not overlap. "Statistically significant" usually refers to a 95% confidence interval.

Invasive

Describes a malignant cancer or tumor that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Generally, the invasive stages are either "localized," "regional," or "distant."

Rate

The number of cancer cases or deaths per 100,000 population. (See Crude Rate and Age-Adjusted Rate, above.)

SEER

The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute is a group of central cancer registries in the United States that collect and submit data on cancer incidence, prevalence, mortality, survival, stage at diagnosis and other statistics to the National Cancer Institute. The National Cancer Act of 1971 mandated the collection, analysis, and dissemination of data useful in the prevention, diagnosis, and treatment of cancer, leading to establishment of the SEER Program.

Stage of Disease at Diagnosis

Stage provides a measure of disease progression, detailing the degree to which the cancer has advanced. Two methods commonly used to determine stage are AJCC and SEER historic. The AJCC method is more commonly used in clinical settings, while SEER has standardized and simplified staging to ensure consistent definitions over time. WISH provides stage data based on the SEER method:

Geographic Areas: Wisconsin and Region

In Situ: A small, early cancer that is confined to the cells in which the cancer began and that has not invaded or penetrated the surrounding tissue.
Localized: Cancer that is limited and confined to the organ of origin, without evidence of spreading to surrounding organs and tissues.
Regional: Cancer that has spread beyond the organ of origin to an adjacent organ, tissue or lymph nodes.
Distant: Cancer that has spread or metastasized from the primary site of origin to distant organs, tissue or lymph nodes.
Unknown/Unstaged: Insufficient information is available to determine the stage or extent of the tumor at the time of diagnosis.

Geographic Area: County

In Situ: A small, early cancer that is confined to the cells in which the cancer began and that has not invaded or penetrated the surrounding tissue.
Localized: Cancer that is limited and confined to the organ of origin, without evidence of spreading to surrounding organs and tissues.
Late: Cancer that has spread beyond the organ or origin to an adjacent organ, tissue or lymph nodes (regional) or has spread or metastasized to distant organs, tissue or lymph nodes (distant).

Standard Million Population: A standard million population for a geographic area is shown in a table giving the number of people in each age group (0, 1-4, ... , 85+) out of a theoretical cohort of 1,000,000 people that is distributed by age in the same proportion as the population.
Standard Population: A standard population for a geographic area, such as the U.S. or the world, is based on the proportions of the population falling into the age groups 0, 1-4, 5-9, ... , 80-84, and 85+.