In exercise 1a we calculated trends for malignant breast cancer for females in the SEER 22 registries for the entire time period 2000-2021. By reviewing the rates in exercise 1a, it appears that there may be different trends. The rates are generally declining from 2000 until around 2005, then they begin rising for the remaining years (with a notable exception in 2020). In this exercise, we will use SEER*Stat to calculate trends for two time periods, 2000-2005 and 2006-2021.

Is the APC for 2006-2021 significantly different from the APC for 2000-2005 (p < 0.05)?

Key Points

Use the dictionary editor to create a variable called "Year of diagnosis (2000-2005, 2006-2021)". This variable should have 2 groupings, one for each of the time periods. Once this variable is created, it will appear as a choice in the Trend Variable control on the Statistic Tab.

SEER*Stat can test whether an APC over one time period significantly differs from an APC for a non-overlapping time period. The first time period defined in the trend variable is used as the base time period and each subsequent time period is compared to the base.

SEER*Stat cannot determine when the changes in trends occur. This is one of the main differences in SEER*Stat and the Joinpoint Trend Analysis Software. Therefore, for this exercise we have pre-determined the two time periods.

SEER*Stat's export feature provides a method to create a generic ASCII text file containing the age-adjusted rates. This file can be used as the input data file in Joinpoint.

Step 1: Open Exercise 1a's Matrix and Retrieve the Session

SEER*Stat matrix files include the session information used to generate the table. This information serves as documentation for the results and provides a convenient method for generating similar statistics.

  • Open your saved matrix file from exercise 1a. If you did not save the file, use the file key.trends1a.sim.
  • Open the Matrix menu and choose Retrieve Session.
  • Two windows should now be open in SEER*Stat. Close the Matrix window and begin working in the Rate Session window.

Step 2: Dictionary

  • Open the Dictionary from the File menu or use the option on the toolbar.
  • Open the "Race, Sex, Year Dx, Registry, County" folder, click on the "Year of Diagnosis" variable, then click Create.
  • Name the new variable "Year of diagnosis (2000-2005, 2006-2021)".
  • Delete all of the existing groupings.
  • Highlight all of the values from 2000 to 2005 (inclusive) and click Add. Title the new grouping "2000-2005".
    • To highlight a continuous range of values, click on the first value in the range, then hold down your SHIFT key while you click on the last value in the range.
  • Highlight all of the values from 2006 to 2021 (inclusive) and click Add. Title the new grouping "2005-2021".
  • Click OK to save the user-defined variable, then click Close to exit the Dictionary.

Step 3: Statistic Tab

On the Statistic tab:

  • Change the Trend Variable to the "Year of Diagnosis (2000-2005, 2006-2021)" variable that you just created.

Step 4: Output Tab

On the Output tab:

  • Edit the title of your matrix, if desired.

Step 5: Execute the Session

  • 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 6: Check Your Results