The concept of
describing disease by stage or extent was introduced in
1929 by the League of Nation's World Health Organization.
Staging is a common language developed by medical professionals
to communicate information about a disease to others.
The disease can be any acute or chronic disease such as
cancer, diabetes, acquired immunodeficiency |
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syndrome (AIDS), cardiovascular disease, or rheumatoid arthritis.
The first primary site so described was cancer of the cervix.
Staging for cancer has evolved over many years. Many groups
have developed different staging systems. Some staging systems
cover all sites; others are limited to particular ages of
patients, histology, sites, study groups, or medical specialties.
This learning module briefly discusses common staging schemes
and classifications. The three most common staging systems
used in hospital and central registries are discussed in detail.
Staging is a shorthand method for describing disease. A coded
format, such as a numerical system with increasing values
meaning more involvement or severity, allows electronic analysis
of cases with similar characteristics.
A short definition for staging is "the grouping of cases
into broad categories based on extent of disease." Extent
of disease is a detailed description of how far the tumor
has spread from organ or site of origin (the primary site).
Extent of disease is an anatomic categorization using descriptors
to group individual cases in relation to the human body.
As stated in the National Cancer Registrars Association Workbook
for Staging Cancer,
Classification is the process of grouping cases based
on specific criteria. Classification is an orderly arrangement
showing relationships among groups. Classification does
not necessarily imply a prognosis.
The relationship between staging, extent of disease
and classification is: extent of disease is a type of classification
(based on human anatomy) and pertains to an individual case.
Staging is coded shorthand or a notation describing disease
in more general terms. By staging, characteristics about
a case (precise extent of disease information) can be grouped
into categories. Thus staging translates extent of disease
classification about individual cancers into groups that
can be studied or evaluated for prognostic significance.
Elements to be considered in any staging system are the primary
tumor site, tumor size, multiplicity (number of tumors), depth
of invasion and extension to regional or distant tissues,
involvement of regional lymph nodes, and distant metastases.
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