Variations in Guideline-Concordant Breast Cancer Adjuvant Therapy in Rural Georgia.

Adjuvant therapy is an important component in the management of breast cancer. Receipt of indicated adjuvant chemotherapy, radiation, and hormonal therapy significantly reduces disease recurrence and improves survival among women with early-stage breast cancer (Clarke et al. 2005; Early Breast Cancer Trialists’ Collaborative Group 2005). The National Institutes of Health (NIH) and a number of other leading medical organizations have developed evidence-based guidelines and recommendations regarding the use of adjuvant therapy for breast cancer (Eifel et al. 2001; National Comprehensive Cancer Network 2014). Despite the documented health benefits and recommendations, receipt of adjuvant therapy varies by several nonclinical factors such as race, health insurance, socioeconomic status (SES), and treatment facility characteristics (Griggs et al. 2007; Byers et al. 2008; Wu et al. 2008, 2012; Bhargava and Du 2009; Buist et al. 2009; Yen et al. 2010; Freedman et al. 2011). For example, black women have been shown to be less likely to receive adjuvant chemotherapy (Bhargava and Du 2009; Freedman et al. 2011) and hormonal therapy (Freedman et al. 2011). Compared with private insurance, having Medicaid insurance has been shown to be associated with lower rates of guideline-concordant chemotherapy (Wu et al. 2012). SES has been shown to be associated with breast cancer treatment patterns (Griggs et al. 2007; Byers et al. 2008; Wu et al. 2012), with patients of lower SES experiencing reduced rates of guideline-concordant chemo- and hormonal therapy (Wu et al. 2012). Receipt of adjuvant therapy may depend on treatment facility characteristics, with higher rates of guideline-concordance reported at American College of Surgeons’ Commission on Cancer (CoC)-approved cancer centers (Wu et al. 2012). Increasing age is inversely associated with adjuvant therapy use (Buist et al. 2009; Yen et al. 2010). Although previous studies have provided insight into the factors potentially influencing receipt of adjuvant therapy, little is known about the delivery of adjuvant therapy in nonmetropolitan settings. Rural breast cancer patients may be less likely to receive new treatments due to slower adoption of new technologies in rural locations. Rural patients may also face additional barriers to treatment, such as a lack of experienced providers, lack of technological support, and longer travel distances (Arrington et al. 2013). The present study examines the delivery of adjuvant therapy for breast cancer in the largely rural region of southwest Georgia (SWGA). Specifically, we examine the factors associated with receiving guideline-concordant (1) adjuvant chemotherapy, (2) adjuvant radiation therapy, and (3) adjuvant hormonal therapy, considered both individually and for all adjuvant therapies jointly, among SWGA breast cancer patients. This study presents an innovative approach to constructing a summary measure of “guideline-concordance” when there are multiple possible treatment components (here, different types of adjuvant therapy following breast cancer surgery) and the recommended treatment package for a patient is conditional on her particular clinical circumstances. Whether a patient is guideline-concordant, so defined, becomes an important indicator of the quality of cancer care. Because the summary measure is a two-level (Yes/No) variable, the patient- and provider-level determinants of variations in guideline-concordance can thus be investigated directly through binary logistic regression. In addition, this study examines guideline-concordance in breast cancer treatment within an important and relatively understudied segment of the U.S. population.