Stage at Diagnosis

Summary Stage

Stage measures how far a cancer has spread from its origin. CDC's National Program of Cancer Registries and the National Cancer Institute's Surveillance, Epidemiology, and End Results Program use the Summary Stage staging system. Summary Stage characterizes invasive cancers as localized, regional, or distant.1

• Localized cancer is confined to the primary site.
• Regional cancer has spread directly beyond the primary site (regional extension) or to regional lymph nodes.
• Distant cancer has spread to other organs (distant extension) or remote lymph nodes.1
• Some cancers are unstaged, or the stage is unknown or unspecified.

Stage categories are different for two cancer sites:

• For brain and central nervous system tumors, the regional and distant categories have been combined.
• For urinary bladder tumors, in situ primaries are included as a category.

In the U.S. Cancer Statistics Data Visualizations tool, stage is classified using the Merged Summary Stage variable. Merged Summary Stage data are suppressed for testis cases due to a data quality issue.

How stage distribution data are presented

Stage distribution data are presented as case counts and percentages for two groups:

• The first group includes localized, regional, distant, and unstaged cases. Including unstaged cases helps quantify the amount of missing data and enables comparisons with other studies using this categorization. However, including unstaged cases will underestimate the percentages of the other stage categories.
• The second group includes only the known stage categories (localized, regional, and distant). Excluding unknown stage provides better estimates of the stage category percentages.

Frequencies and percentages are suppressed for groups with fewer than 16 cases. In addition, complementary cell suppression is done to suppress data for both sexes combined if data are suppressed for one sex. For more information, see Suppression of Rates and Counts.