This exploratory population-based study will identify reasons why rural women 65 years of age and older in Iowa are less likely than their urban counterparts to receive radiation therapy (XRT) following conservative surgery (BCS) for stage I-II breast cancer. XRT is recommended by the NIH for these women, but rural elderly women are 1.7 times less likely to receive XRT according to data from the Surveillance, Epidemiology, and End Results (SEER) program for reasons that are unclear. Review of the previous proposal (submitted 2/1/2000) emphasized a need for better characterization of the conceptual model and measures used, including physician practices and recommendations, and the implications of the study. Each of these issues is addressed in this revision. Use of a geographic information system (GIS) and a multilevel approach have been added also. In addition to the investigation of rural-urban differences in XRT use in terms of demographic, clinical, psychosocial, and geographic factors, we have added ecological factors from the 2000 census. All these factors will be tested for their association with XRT. Women ages 65 and older with stage I-Il breast cancer who have had BCS will be identified from the Iowa SEER registry. Women with cognitive impairment, severe hearing loss, and those who do not speak English will be excluded. Data will be collected using telephone interviews, the Iowa SEER database, pathology reports, and a GIS. We will validate patients' responses to questions about receipt of adjuvant therapy against the SEER data. We will compare demographic, clinical, psychosocial, and geographic factors between the two following groups of women: 1) women interviewed 4-6 months following diagnosis, and 2) women interviewed 2 years following diagnosis. If no differences in these factors are found between the two groups, the data will be pooled in the analysis to determine whether rural women are less likely to receive XRT while controlling for important factors. Results will identify reasons for rural-urban differences in XRT use and may guide development of interventions that address modifiable factors associated with underutilization of XRT among rural women.
