Examine trends in age-adjusted incidence rates for malignant breast cancer for females in the SEER 9 Registries for 1975-2015. 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 1975-2015.

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 1975-2015, the only years for which all 9 registries have cases in the database. Though the database used has data for cases diagnosed starting with 1973, the Seattle-Puget Sound and Atlanta registries joined the SEER program in 1974 and 1975, respectively.

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 9 Regs Research Data, Nov 2017 Sub (1973-2015) <Katrina/Rita Population Adjustment>".
  • The Age Variable should be "Age recode with <1 year olds".

Step 3: Dictionary

It is necessary to create a new trend variable based on year of diagnosis. This database contains data from 1973 through 2015, but we want to examine trends from 1975-2015.

  • Use the Dictionary icon, or select Dictionary from the File menu, to open the Dictionary.
  • 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 (1975-2015)".
  • Delete the 1973 and 1974 groupings.
  • Highlight the 1973-2015 grouping and change the range of values to 1975 through 2015, then click Update. Title the new grouping "1975-2015".
  • 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.

Step 4: 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 new variable you created, "Year of diagnosis (1975-2015)". 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 5: 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, Registry, County.Sex} = 'Female'
    AND {Race, Sex, Year Dx, Registry, County.Year of diagnosis} = '1975', '1976', '1977', '1978', '1979', '1980', '1981', '1982', '1983', '1984', '1985', '1986', '1987', '1988', '1989', '1990', '1991', '1992', '1993', '1994', '1995', '1996', '1997', '1998', '1999', '2000', '2001', '2002', '2003', '2004', '2005', '2006', '2007', '2008', '2009', '2010', '2011', '2012', '2013', '2014', '2015'
  • Edit the "Other (Case Files)" selection statement to read:
  • {Site and Morphology.Site recode ICD-O-3/WHO 2008} = 'Breast'

It is not necessary to include the "SEER registry" in the selection statement, since we are interested in trends in all registries covered by the database.

Step 6: 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 7: Output Tab

  • Give your matrix a title, such as:
    Malignant Female Breast Cancer Incidence Trends
    SEER 9, 1975-2015
    Trends Exercise 1a

Step 8: 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 9: Check Your Results