mortality
The number of deaths during a specific time period.

percent change
The percent change (PC) in a statistic over a given time interval is Percent change = (Final value - Initial value) / Initial value * 100. A positive PC corresponds to an increasing trend, a negative PC to a decreasing trend.

prevalence
The number of cases alive on a certain date.

primary tumor
The original tumor.

relative survival rate
A specific measurement of survival where the rate is calculated by adjusting the rate to remove all causes of death except cancer. It is the ratio of a cancer patient's chance of surviving a given time interval to that of an average person of the same age and sex.

reporting delay
The time elapsed before a diagnosed cancer case is reported to the NCI. Currently, the NCI allows a standard delay of 22 months between the end of the diagnosis year and the time the cancers are first reported to the NCI in November, almost two years later.

SEER
Surveillance, Epidemiology, and End Results (SEER) Program of the NCI is a collection of population-based cancer registries in the United States which collect and submit cancer incidence and follow up data 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 the establishment of the SEER Program.

SEER registries
SEER Program collects cancer incidence and survival data from the SEER registries, geographic areas selected for inclusion in the SEER Program based on their ability to operate and maintain a high quality population-based cancer reporting system and for their epidemiologically significant population subgroups.

spatial correlation
A measure of the tendency for places that are near to each other to have more similar (positive correlation) or dissimilar (negative correlation) values of their statistics.

stage
The extent of a cancer within the body. If the cancer has spread, the stage describes how far it has spread from the original site to other parts of the body.

standard error
The standard error of a rate is a measure of the sampling variability of the rate.

standard million population
A standard million population for a geographic area is a table giving the number of persons in each age group 0, 1-4, ... , 85+ out of a theoretical cohort of 1,000,000 persons that is distributed by age in the same proportions as the population.

standard population
A standard population for a geographic area, such as the U.S. or the world, is a table giving the proportions of the population falling into the age groups 0, 1-4, 5-9,…, 80-84, and 85+.

statistically significant
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.

surveillance data (cancer)
Measures of cancer incidence, morbidity, survival, and mortality for persons with cancer. It also includes the assessment of genetic predisposition, environmental and behavioral risk factors, screening practices, and the quality of care from prevention through palliation.

survival
The proportion of patients alive at some point after the diagnosis of their cancer.

trends over time
The change in rate over time expressed as an annual percent change.