Women
with Localized Breast Cancer
Selecting Mastectomy Treatment,
Iowa, 1991-1996
Gerard Rushton, PhD; Michele West, PhD
MAP
1. Number of cases of localized breast cancer,
by zip code area, Southeast Iowa, 1991-1996
(click
on map for an enlarged view)
MAP
2. Number of women selecting mastectomy
per 1000 cases of localized breast cancer,
by county, Iowa, 1991-1996.
(click
on map for an enlarged view)
MAP
3. Smoothed (spatially filtered) map of number
of women selecting mastectomy
per 1000 cases of localized breast cancer,
Iowa, 1991-1996
(click
on map for an enlarged view)
Software used : Maps 1 and 2 were prepared using Maptitude by Caliper Corporation. For Map 3, DMAP (University of Iowa) was used to compute the grid. The filter values and contouring were produced with TransCAD by Caliper Corporation.
In 1990, the National Institutes of Health declared that breast-conserving treatment (excision of tumor, axillary node dissection, and breast irradiation) was preferable for the majority of women with early stage breast cancer, providing survival rates equal to those seen with total mastectomy. Yet, for 1991-1995, the Iowa Cancer Registry reported higher rates of mastectomy for histologically confirmed cases of localized breast cancer than other registries for which comparable information is available.
Drs. Rushton and West used GIS technology to identify areas in Iowa with high rates of mastectomy among women with localized breast cancer. As shown in Map 1 for a part of Southeastern Iowa, most zip code areas have so few localized breast cancer cases that a valid choice rate could not be determined for them. (The large circles show the size of the spatial filter used to generate Map 3.) Spatial aggregation of the data was required. Map 2 shows choice rates by county of residence for the whole state. Map 3 is a "smoothed" map that shows the geographic pattern of choice rates for mastectomy in more detail than the county-level map. One hypothesis accounting for this geographic pattern is that areas close to radiation treatment centers -- shown on the map -- have lower mastectomy rates.
Matthew Airola, MA, and Aniruddha Banerjee, MA, Department of Geography, University of Iowa, prepared these maps. The National Cancer Institute and the Iowa Cancer Registry provided support for the study for which these maps were developed.
Matthew Airola, M.A.
Aniruddha BanerjeeDrs. Rushton and West are with the University of Iowa. Dr. Rushton is a Professor in the Department of Geography, and Dr. West is an Assistant Research Scientist in the Department of Preventive Medicine, College of Medicine.
Dr. Gerry Rushton
Dr. Michele WestPublic Health Reports 1999;114:370-371
This article reproduced with the permission of Oxford University Press.
| Address correspondence to: | Dr.
Rushton Dept. of Geography, 316 JH University of Iowa Iowa City, IA 52242 |
| telephone: | 319-335-0162 |
| fax: | 319-335-2725 |
| e-mail: | gerard-rushton@uiowa.edu |
| websites: | http://www.uiowa.edu/~geog
and http://www.uiowa.edu/~geog/health/ |