Examine trends in age-adjusted incidence rates for malignant breast cancer for females in the SEER 9 Registries for 1975-2018. Use rates, age-adjusted to the 2000 U.S. Standard Population in the trend calculations. Specifically, calculate the Percent Change (PC) and Annual Percent Change (APC) for the entire time period 1975-2018.

Key Points

To calculate the percent change and annual percent change in rates, you must select one of the "Trends" options in the Statistic box on the Statistic Tab. The time periods used for the trend calculations are specified as groupings in a "Trend Variable". The "Year of diagnosis" and user-defined variables derived from "Year of diagnosis" are the only possible incidence trend variables. APCs and PCs will be calculated for groupings with three or more consecutive years. The rates for the individual years within these time periods will always be displayed in the output (it is not necessary to define groupings for the individual years). Groupings of 1 or 2 years will be ignored.

In this exercise, you will calculate trends in rates for cases diagnosed between 1975-2018, the years for which all 9 registries have cases in the database.

By default, APCs are calculated in SEER*Stat using the Weighted Least Squares method. Standard errors are required to calculate APCs using this method and, therefore, are always included with the results.

Step 1: Create a New Rate Session

  • Start SEER*Stat.
  • From the File menu, select New > Rate Session, or use the Rate icon on the toolbar.

Step 2: Data Tab

On the Data Tab:

  • Select the database "Incidence - SEER Research Data, 9 Registries, Nov 2020 Sub (1975-2018)".
  • The Age Variable should be "Age recode with <1 year olds".

Step 3: Statistic Tab

Choose the following settings on the Statistic tab. Most of these settings are the default values.

  • Set the Statistic to Trends (Age-Adjusted). The other controls you need to use on this tab will not all be available until you choose this option.
  • The Standard Population should be "2000 U.S. Std Population (19 age groups - Census P25-1130)".
  • The Age Variable should be "Age recode with <1 year olds".
  • The Trend Variable should be the default "Year of diagnosis" variable. All available variables based on year of diagnosis will be listed in the Trend Variable selection list.
  • The PC End Points should be One Year.
  • The APC Calculation method should be Weighted Least Squares.
  • The Tiwari Modification for confidence intervals should be used.

Step 4: Selection Tab

On the Selection tab:

  • Mark only the Malignant Behavior checkbox in the Select Only section.
  • Edit the "Race, Sex, Year Dx, Registry, County (Pop, Case Files)" selection statement to read:
    {Race, Sex, Year Dx.Sex} = ' Female'
  • Edit the "Other (Case Files)" selection statement to read:
    {Site and Morphology.Site recode ICD-O-3/WHO 2008} = 'Breast'

Step 5: Table Tab

There are no table variables required. The trend variable, "Year of Diagnosis", will automatically be displayed in the output matrix as a row variable.

Step 6: Output Tab

  • Give your matrix a title, such as:
    Malignant Female Breast Cancer Incidence Trends
    SEER 9, 1975-2018
    Trends Exercise 1a

Step 7: Execute the Session

  • Use the Execute icon, or select Execute from the Session menu, to execute the session.

A dialog will display the progress of the job. When the job completes, a new window will open containing the output matrix.

Step 8: Check Your Results