What to know
This page provides a glossary of terms and acronyms related to United States Cancer Statistics.
A
Adult cancer: Cancer found in a person aged 20 years or older.
Age distribution of a population: The number of people in particular age categories. Example: The 2000 US standard population is based on the proportion of the 2000 population in specific age groups (younger than 1 year, 1 to 4 years, 5 to 9 years, 10 to 14 years, 15 to 19 years, and so on up to 85 years or older).
Age range: Age in years, grouped in a category (for example, younger than 1, 1 to 4, 5 to 9, and so on up to 85 or older).
Age-adjusted rate: Incidence or mortality rate adjusted to the age distribution of a standard population to allow for comparison among populations with different age distributions; for example, rates are age-adjusted to the 2000 US standard population.
B
Basal cell skin cancer: A malignant skin tumor composed of cells similar to those from the basal cell layer of the epidermis. Because of the estimated large volume, many cancer registries do not register basal cell skin cancer except for selected sites, such as skin of the external genital organs (for example, vulva, penis, scrotum).
C
Case count: The number of people diagnosed with cancer in a given time period.
CDC: Centers for Disease Control and Prevention.
Census division: Geographic groups of states. For example, the New England division includes Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont.
Census region: Geographic groups of states comprising of several U.S. Census divisions. For example, the New England and Middle Atlantic divisions are in the Northeast Region.
Childhood cancer: Cancer found in a person younger than 20 years of age. Due to the high incidence rate seen in children younger than 1 year old, the following age categories are used for data presentation: younger than 1 year old, 1 to 4 years, 5 to 9 years, 10 to 14 years, and 15 to 19 years. See the International Classification of Childhood Cancer (ICCC) for more information about the classification system. Rates are per 1 million when the ICCC system is used. Rates are per 100,000 when the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) site group listing is used.
Confidence interval (CI): A range of values for a rate that will include the true value of the rate a given percentage of the time. Example: 95% CI includes the true value of the rate 95% of the time.
Crude rate: The absolute number of cases or deaths in a given population during a given time frame divided by the population in the given geographic area. No adjustments are made when a crude rate is presented.
D
Death rate: The number of deaths in a given population during a given time frame in a given geographic area per 100,000 people.
Deaths: The number of people who died of cancer in a given time period.
I
IBD: Intrahepatic bile duct.
In situ cancer: An early cancer that is present only in the layer of cells in which it began.
Incidence rate: The number of new events in a given population during a given time frame in a given geographic area per 100,000 people.
International Classification of Childhood Cancer (ICCC): Classification of childhood cancer based on tumor histology. At the time the World Health Organization's International Agency for Research on Cancer published their first monograph on childhood cancer in 1988, Dr. R. Marsden published an annex giving a classification scheme for childhood cancer that consisted of 12 groups based chiefly on histologic type. The classification by Marsden has been modified and is now called the International Classification of Childhood Cancer.
International Classification of Disease for Oncology (ICD-O): A classification system used by tumor or cancer registries to code the site and the histology of the cancer, usually from a pathology report.
Invasive cancer: Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues.
K
Kaposi's sarcoma: Cancer of the connective tissue such as cartilage, bone, fat, muscle, and blood vessel.
M
Mesothelioma: Cancer that generally occurs in the chest, abdominal region, and areas surrounding the heart. It is typically associated with exposure to asbestos.
Metropolitan area: An extended urban area near or surrounding a major city. The SEER metropolitan area registries included in the report are Atlanta, Detroit, Los Angeles, San Francisco-Oakland, San Jose-Monterey, and Seattle-Puget Sound.
Morphology: The types of cancer that occur.
Mortality: The condition of being subject to death. When rates are discussed, "death rate" is used to coincide with the National Vital Statistics System data presentations.
N
NAACCR: North American Association of Central Cancer Registries.
National partner organizations: Cancer-related organizations that value the commitment to successful cancer registration and surveillance.
NCHS: National Center for Health Statistics, CDC.
NCI: National Cancer Institute.
NPCR: National Program of Cancer Registries, CDC.
NPCR Scientific Working Group: Members are charged to enhance the collection and dissemination of cancer surveillance data. Members include NPCR-funded or NPCR/SEER-funded central cancer registry and NPCR staff.
NOS: Not otherwise specified.
NVSS: National Vital Statistics System.
P
Population: The number of inhabitants of a given geographic area.
Prevalence: The number of people with a specific disease or condition in a given population at a specific time. This measure includes both newly diagnosed and pre-existing cases of the disease. It is different from incidence, because incidence measures only the number of newly diagnosed cases in a given population at a specific time. There are different types of prevalence. For example, annual prevalence is the number of persons with the disease at any time during a year, period prevalence is the number of persons with the disease at any time during a specified number of years, such as the last 10 years, and limited-duration prevalence is the number of people alive on a certain day with the disease during a specified number of years (such as the last 5 or 19 years).
Primary site: The location or organ (site) in the body where the cancer first occurred.
R
Ranking: Ordering from highest to lowest based on magnitude of observed values.
Rate: A basic measure of disease frequency, which takes into account the number of cases or deaths and the size of a population. See Age-Adjusted Rate, Crude Rate, Death Rate, or Incidence Rate.
Relative survival: Estimates the percentage of cancer patients who will not have died from their cancer a certain time after diagnosis. It is calculated as the ratio of the observed proportion of cancer patients surviving for a specified time after cancer diagnosis (for example, 5 years) to the expected proportion of persons with similar characteristics (for example, same sex, age, and race) who would be alive for the same period of time. It estimates whether the cancer shortens life.
S
SEER: The National Cancer Institute's Surveillance, Epidemiology, and End Results program.
SEER site groups: Groups of major cancer sites that are commonly used to report cancer incidence data; for example, colon and rectum, lung and bronchus.
Site: See Primary Site.
Squamous cell skin cancer: A malignant tumor having characteristics of squamous cells. Because of the estimated large volume, many cancer registries do not register squamous cell skin cancer except for selected sites, such as skin of the external genital organs (for example, vulva, penis, scrotum).
Stage: A measure of disease progression, detailing the degree to which the cancer has advanced. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.
U
US Census division: Geographic groups of states. For example, the New England division includes Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont.
US Census region: Geographic groups of states comprising of several US Census divisions. For example, the New England and Middle Atlantic divisions are in the Northeast Region.