An identification of the type of classification relating to the site of the cancer, used to record cancer staging.

National Codes:

1	Nottingham Prognostic Index (Breast)
2	Dukes (Colorectal)
3	Limited disease or Extensive disease (Small Cell Lung Cancer)
4	FIGO - Federation Internationale de Gynecologie Obstetrique (Gynaecological)

References:
National Cancer Data Set Version 1.3_ISB October 2002 

This attribute is also known by these names:

Context	Alias
plural	SITE SPECIFIC STAGING CLASSIFICATIONS