The Cancer Registry community collaborated on a survival algorithm that uses day information in the survival calculation. One goal of this activity was to harmonize as much as possible with efforts such as CONCORD. It may also be possible to evaluate other methods that require more continuous survival data.

Since day is a confidential variable, the process was established to calculate these fields at the registry, and submit them with their data submissions.

It is very important that registries do not recode any missing date fields for Date of Diagnosis or Date of Last Contact prior to running the algorithm to create these fields. One purpose of the algorithm is to standardize specification of missing month and day fields.

Descriptions of the Fields and Algorithm

  1. Descriptions of the eight survival variables, three of which are recoded date fields (where values are assigned for missing date components).
  2. All SEER, NPCR, and NAACCR registries submit these fields, which are calculated using the algorithms library. We have a SAS program available to others, to allow them to match the algorithm. The SAS program is not maintained, but the logic has not changed. Anyone interested in using the SAS code will need to update the input/output files, input/output statements, and cutoff date.
  3. A document describing the logic that is used to assign valid date values when month and/or day of either date is missing.

Additional Information

If you have questions about the process (i.e. Which option should I choose?), please contact your standard setter.

If you have a technical question about the survival calculation or anything else, please email seerweb@imsweb.com