Survival Calculation

The survival duration parameters establish if survival time will be computed by SEER*Stat or if a field containing pre-calculated survival duration will be used.

Pre-calculated Duration

This option will be available if there are one or more variables in the selected database that contain pre-calculated survival duration values.

When this option is selected, the begin and end date controls will be disabled since SEER*Stat will not be computing duration. However, there are begin and end date variables that are associated with the duration field that are used in the analysis, e.g., appropriate selection of expected survival tables and user change of study cutoff date.

Duration

The Duration contains the pre-calculated survival duration variables available for each individual case in the selected database. Typically, pre-calculated survival duration is available in months but has been calculated using complete dates (day, month, year).

For information regarding pre-calculated survival fields in SEER provided databases, see: https://www.seer.cancer.gov/survivaltime

Calculated from Dates

When this option is selected, the system calculates the case survival duration from a begin date and end date stored on each record. The begin date is typically selected to be the date of diagnosis and the end date, the date of death or last contact. With each ending date of calculation, there is an associated vital status field. The vital status indicates whether the case was alive or dead at the end date.

When creating a life table, SEER*Stat calculates the number of cases alive at the beginning of each survival interval. Each case is counted as entering the first interval as alive. The case either survives into the next interval or its survival time terminates somewhere within the current interval. If the case does not survive into the next interval, it is counted as either dying during the current interval or the vital status indicates that it is alive, but does not have enough survival time to go in the next interval. In the latter case, the case is counted as lost to follow-up or withdrawn during the interval depending on the relationship between its End Date of Calculation and the Lost to Follow-up Date.

Begin Date

The Begin Date contains the date variables available to initiate the calculation of survival duration for an individual case. Typically, the begin date is the date of diagnosis. If the incidence database has only one date variable suitable for the Begin Date, the list box will be fixed on the only choice. Cases with an invalid Begin Date will not be included in the analysis.

End Date

The End Date contains the date variables available to end the calculation of survival duration for an individual case. Typically, the end date is the date of last follow up or death. If the incidence database has only one date variable suitable for the End Date, the list box will be fixed on the only choice. Cases with an invalid End Date will not be included in the analysis.

Vital Status

The Vital Status label displays the Vital Status field associated with either the selected end date of calculation for the database or the pre-calculated duration variable. Vital Status fields indicate whether the person was alive (censored) or dead at the coded end date of calculation. The Vital Status variable is used when Observed Survival Only, Relative Survival, or Crude Probability of Death Using Expected Survival is selected on the Statistics tab. Cause-Specific Survival and Crude Probability of Death Using Cause of Death use the user-defined Definition of Cause of Death to determine whether a case is censored or dead.

Study Cutoff Date

Select the Month and Year that you would like your analysis to end. A patient's survival time is not calculated beyond the study cutoff date.

When a patient survives beyond the study cutoff date, survival duration is stopped at the study cutoff date. Sometimes there are patients who survive beyond the study cutoff date but are dead at the date of last contact. The vital status for these patients is changed to alive and their duration is computed up to the study cutoff date because they were alive through the end of the study. Any patient whose begin date is beyond the study cutoff date is removed from the analysis.

Presumed Alive

When this option is selected, all persons not known to be deceased will be considered to be alive through the Study Cutoff date.

Censor when Attained Age Exceeds Table Max

With this option unchecked, when the attained age for a case exceeds the maximum age in the expected rate table, then from that point on the maximum table age is used for any expected rate look-up.

Regardless, any case with an age at diagnosis greater than the expected rate table maximum age will be automatically removed from the survival analysis.