Tumor or Neoplasm - an abnormal growth of tissue; tumors can be benign (not cancer) or malignant (cancer).
Cancer - a group of more than 100 diseases characterized by uncontrolled growth and spread of abnormal cells.
Carcinogen - any substance that causes cancer or helps cancer develop.
Risk factor - anything that increases a person's chance of getting a disease such as cancer.
Diagnosis - identifying a disease by its signs, symptoms, and laboratory findings; usually the earlier a diagnosis of cancer is made, the better the chance for cure.
Stage at diagnosis - describes how far cancer has spread by the time it is diagnosed:
in situ - a very early cancer found in only a few layers of cells and called non-invasive because it has not invaded nearby tissue, highly curable
local - an invasive cancer confined entirely to the organ of origin
regional - an invasive cancer that has extended beyond the limits of the organ of origin into surrounding organs or tissues and/or into regional lymph nodes
distant - an invasive cancer that has spread to parts of the body remote from the primary tumor either by direct extension or by discontinuous metastasis.
Metastasis - the spread of cancer cells to distant areas of the body through the lymph system or the bloodstream.
Primary Site - the site in the body where the cancer began; usually cancer is named after the organ in which it started, e.g. breast cancer. It is possible to have more than one primary cancer or multiple primaries at the same site.
Histologic classification of cancer - there are many types of cancer even within the same organ of origin; the pathologist classifies cancers based on microscopic examination:
carcinomas - cancers of the epithelium (cells that cover the external surface of the body, line the internal cavities, or are derived from the linings that form glands); at least 80 percent of cancers are carcinomas and nearly all breast cancers are a form of carcinoma.
lymphomas - cancers of the lymph nodes, bone marrow, and occasionally other organs; about 5 percent of cancers are lymphomas.
sarcomas - cancers of the connective tissue (fat, cartilage, vessels, nerves, and muscles).
primitive or mixed cell - rare types of cancers in different organs.
International Classification of Diseases - Oncology (IDC-O) - the cancer classification system generally accepted for use in cancer registries; published by the World Health Organization.
Epidemiology - the study of the patterns of the occurrence of disease in human populations and the factors that influence these patterns.
Incidence - the number of newly diagnosed cases of a disease occurring in a specific population during a specific time period.
Incidence rate (or crude incidence rate) - the number of newly diagnosed cases of a disease in a specific population during a specific time period per "x" number of people; usually the time period is one year and "x" number of people is 100,000.
Age-specific incidence rate - the number of newly diagnosed cases of a disease in a specific age group in a specific population over a specific time period per "x" number of people in the specific age group; usually five-year age groups (0-4, 5-9, 10-14, etc.), usually the time period is one year and "x" number of people in the specific age group is 100,000.
Age standardization (or age-adjustment) - the statistical adjustment of crude rates for differences in age distributions in order to compare rates in different populations; there are two types of standardization, direct and indirect.
Age-adjusted incidence rate - a summary incidence rate that takes into account the age distribution of the population. This is routinely done so that comparisons can be made from year to year. Age-adjustment also enables comparisons among geographic areas. There are several methods to age-adjust; direct standardization is the method most commonly used. With this method the age-specific incidence rates of the population of interest (e.g. New Jersey) are applied to a standard population (e.g. 1970 U.S. population).
Mortality - the number of deaths due to a disease in a specific population over a specific time period.
Mortality rate, age-specific mortality rate, age-adjusted mortality rate - analogous to the incidence rate, age-specific incidence rate, and age-adjusted incidence rate, except deaths rather than newly diagnosed cases are the numerator.