Case Scenarios

The final section of this module presents case scenarios based on questions submitted to SEER through Ask a SEER Registrar. These examples were carefully selected to demonstrate the application of the Multiple Primary Rules (MP) and the Primary Site and Histology Rules (PH). The scenarios also include guidance on diagnostic confirmation, EOD, Summary Stage, and Mets at Dx. While they do not cover every M or PH rule, they highlight the most commonly encountered ones.

These cases are designed to walk you through the rule process, with a strong focus on determining the primary site.

Updated: December 2, 2025