Date of initiation of the first course therapy for the tumor being reported, using the SEER definition of first course. See also Date 1st Crs RX CoC [1270]. See Chapter V, Unresolved Issues, for further discussion of the difference between SEER and CoC items. See Data Descriptor Table for date format. 
 
Formerly Date of Initial RX--SEER.

Clarification of NPCR Required Status

Central registries funded by NPCR are required to collect either Date Initial RX SEER [1260] or Date 1st Crs RX CoC [1270].