There is now a sizable cohort of women between the ages of 20 and 40 who are at an elevated risk for breast cancer because their developing breast tissue was exposed to radiation during childhood cancer treatment (
Hewitt, Weiner, & Simone, 2003;
Ries et al., 2007). Survivors of Hodgkin's disease comprise the largest proportion of childhood cancer survivors in the group at risk for secondary breast cancer. However, chest radiation is also routinely used in treatment protocols for metastatic Wilms' tumor and soft tissue sarcomas, as well as for other refractory or recurrent pediatric malignancies. Previous investigations indicate that by 45 years of age, 12% to 20% of young women treated with radiation therapy will be diagnosed with breast cancer (
Bhatia et al., 2003;
Kenney et al., 2004; Taylor, Winter, Stiller, Murphy, & Hawkins, 2006). Thus the risk of breast cancer after chest radiation for a pediatric malignancy rivals that of women with a BRCA mutation, who have an estimated cumulative incidence of breast cancer at age 40 that ranges from 10% to 19% (
Bhatia et al., 2003;
Bishop, 1999;
Ford et al., 1998;
Struewing et al., 1997).
Information about secondary breast cancer following radiation for pediatric malignancies is largely derived from studies of survivors of Hodgkin's disease. The risk of breast cancer in this group begins to increase about 8 years after chest radiation (
Bhatia et al., 2003;
Kenney et al., 2004;
Metayer et al., 2000) and the interval from Hodgkin's disease to breast cancer for both pediatric and adult groups is about 15 to 20 years (
Bhatia et al., 2003;
Cutuli et al., 2001;
Kenney et al., 2004;
Metayer et al., 2000; Taylor et al., 2006;
Wolden et al., 2000). The median age of breast cancer diagnosis is 32 to 35 years old, (
Bhatia et al., 2003;
Kenney et al., 2004; Taylor et al., 2006), which is well below the average age of breast cancer onset (e.g., > 50 years) (
Ries et al., 2007) in the general population and below the age at which most women routinely undergo mammography (e.g., 40 years)(
American Cancer Society, 2007).
Consistent with the general population (
Berry et al., 2005;
Vlastos & Verkooijen, 2007), early detection of breast cancer in the high-risk population of childhood cancer survivors may lead to increased diagnoses of breast cancers at early stages, thereby requiring less invasive treatments, incurring improved outcomes and enhanced quality of life. Annual screening mammography with adjunct breast MRI is recommended for childhood cancer survivors, starting at age 25 or eight years after completion of radiation therapy, whichever occurs last (
Children's Oncology Group, 2006). Among Hodgkin's disease survivors who develop secondary breast cancer, 27% to 100% of the cancers were detected by mammography (
Dershaw, Yahalom, & Petrek, 1992;
Diller et al., 2002;
Wolden et al., 2000); however, many survivors do not adhere to the treatment exposure–based guidelines for screening. For example, only 169 (41%) of 414 survivors at increased risk of breast cancer underwent mammography (
Nathan et al., 2007), and fewer long-term survivors of childhood cancer (21%,
N = 4414) report ever having had a mammogram (
Yeazel et al., 2004) compared to survivors of adult cancers (75%–92%,
N = 4785) (
Bellizzi, Rowland, Jeffery, & McNeel, 2005). There is a critical need to educate and promote mammography screening in this high risk population in order to potentially reduce breast cancer morbidity and mortality.
Quite similar to the general population (
Cui et al., 2007;
Cummings, Whetstone, Shende, & Weismiller, 2000;
Goodwin, Visintainer, Facelle, & Falvo, 2006;
Williams, Lindquist, Sudore, Covinsky, & Walter, 2008) factors that predict mammography utilization in survivors of breast cancer and Hodgkin disease include visits to the oncologist (
Field et al., 2008), gynecologist (
Doubeni et al., 2006), or primary care physician (
Doubeni et al., 2006), having health insurance (
Bober, Park, Schmookler, Medeiros Nancarrow, & Diller, 2007), physician support (
Bober et al., 2007), worry about breast cancer (
Bloom, Stewart, & Hancock, 2006), older age (
Bloom et al., 2006), and higher education and income (
Breen, Yarbroff, & Meissner, 2007). Childhood cancer survivors who are least likely to report receiving routine mammography are younger and express a lack of concern for future health issues (
Yeazel et al., 2004).
In addition to disease and treatment factors, personal and contextual factors influence health behavior choices (
Breslow, Lloyd & Shumaker, 1994;
Cox, McLaughlin, Rai, Steen, & Hudson, 2005;
Cox, McLaughlin, Steen, & Hudson, 2006;
Kraemer, Wilson, Fairburn, & Agras, 2002;
Prochaska, 2005;
Rejeski, Brawley, McAuley, & Rapp, 2000). To describe the multiple influences on survivors' adherence to mammography screening guidelines, we selected the Interaction Model of Client Health Behavior (IMCHB) (
Cox, 1982;
Cox, 2003;
Cox et al., 2006;
Cox et al., 2008a,
2008b,
2008c), which incorporates both intrapersonal and contextual variables and has been adapted to the study of childhood cancer survivors (). The IMCHB incorporates physical, social, cognitive, motivational, affective, provider, and environmental antecedents to health behavior. The original empirical support for the model concepts and their relationships is reported in detail elsewhere (
Cox, 1982,
1984). Briefly, the model comprises three elements: client singularity (the unique intrapersonal and contextual configuration of the individual), client-professional interaction (the therapeutic content and process that occurs between a provider and patient), and health outcomes (the behavior or behaviorally related outcome subsequent to a patient-professional interaction). The model's working hypothesis is that the potential for positive health outcomes increases as the provider intervention is tailored to the unique manifestation of each patient relative to a constellation of their background variables, cognitive appraisal, affect, and motivation.
Structural equation modeling (SEM), which combines factor and path analyses into a comprehensive methodology (
Kaplan, 2000), allowed us to test the hypotheses generated by the conceptual model. SEM tests all hypothesized relationships simultaneously rather than sequentially. Our goal was to identify disease, treatment, survivor, provider, and contextual factors that could be targeted with behavioral interventions to support recommended mammography screening.