Tx Start Date (ACOS)

Field Length:  8

The treatment start date is a case level data item that is calculated by the computer for all records that are entered as a full Abstract Form. It is the date of the initiation of first course definitive therapy for this cancer. The calculation reviews all treatment types except N, including surgeries at regional and distant sites, to determine the earliest start date. If there was no definitive first course therapy recorded, this field will be blank. If the Treatment Start Date = <blank>, then the Date of No First Therapy must be filled in.