Multiple Primary Selections for Prevalence

The Multiple Primary Selection drop-down list at the bottom of the Selection tab in a Limited-Duration Prevalence session provides several options for selecting the specific tumor or tumors of interest for an individual. All prevalence statistics calculated in SEER*Stat are numbers of people who meet the criteria, not the numbers of tumors they have had. This feature is only available when you are using a database in which the records are grouped by person and are in chronological order of diagnosis. For example, the SEER incidence databases are sorted by SEER registry, Patient ID, and Sequence number., making SEER Incidence databases Multiple Primary ready.

Descriptions of the five Multiple Primary Selection options are provided below. They are more easily understood if you consider them as one of two types:

• Options that include, at most, one tumor per person in the analysis.
• Options that include more than one tumor per person in the analysis. All Tumors Matching Selection Criteria is the only option of this type in SEER*Stat.

First Malignant Primary Only (Non-reported Assumed Malignant)

When tumors occur prior to the start of the registry, or prior to the person moving to a SEER catchment area, SEER makes the assumption that these cancers are malignant, as is true of the majority of SEER cancers. Thus, if SEER indicates that the first SEER-registered tumor is the person's second tumor (the other was a non-SEER cancer) then this person's cancers are excluded when using this option.

All Tumors Matching Selection Criteria/One Tumor per Statistic

This option includes all tumors that match the selection criteria. These could include multiple tumors for some individuals; however, each statistic calculated in a Limited-Duration Prevalence session is never based on more than one tumor per person. Please see Using All Tumors Matching Selection Criteria for more information.

First Primary Matching Selection Criteria

This option includes only the individual's first primary tumor in the database that matches the selection criteria, regardless of the sequence number or whether the tumor is malignant. Note that the selection criteria in a Limited-Duration Prevalence session consists not only of the selection statements on the Selection tab, but also of the Prevalence Date and Duration on the Statistic tab. A record will meet the selection criteria only if it matches all the selection statements and occurred within the time period specified by the Prevalence Date and Duration. A warning message will remind you of this when you execute a session using this option.

First Primary Only (Sequence Number = 0 or 1)

This option includes the first tumor for each individual if that tumor matches the selection criteria and has a sequence number equal to 0 or 1. A sequence number equal to 0 indicates that it is the only tumor in an individual's history. A sequence number equal to 1 indicates that it is the first of two or more tumors in the individual's history.

First Primary in Database Only

This option includes the first tumor in the database for each individual if that tumor matches the selection criteria.