California Cancer Reporting System Standards Volume I: Abstracting and Coding Procedures
Refer to the current Multiple Primary and Histology Rules to determine the number of primaries. This applies to cases diagnosed January 1, 2007 forward.
Tumor recurrences only relate to the organ of origin. Metastatic tumors in regional and distant sites are not considered tumor recurrences when applying the MP/H rules.
When determining multiple primaries for solid malignant tumors, do not use a physician's statement to decide whether the patient has a recurrence of a previous cancer or a new primary.
Use the multiple primary rules as written unless a pathologist compares (slide review) the present tumor to the "original" tumor and states that this tumor is a recurrence of a cancer from the previous primary.