Date of initiation of the first therapy for the cancer being reported, using the CoC definition of first course. The date of first treatment includes the date a decision was made not to treat the patient. See STORE for details. 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 1st Crs RX--CoC.

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].