Abstract A85: Breast cancer pathology, receptor status, and patterns of metastasis in a rural Appalachian population

Abstract

Abstract Background: Breast cancer patients in rural Appalachia have a high prevalence of obesity and poverty, together with excessive expression of the triple-negative phenotype. Methods: Clinical records for 687 patients provided data which included tumor receptor status and time to distant metastasis. Breast cancers with the triple-negative phenotype were compared with other receptor combinations. Body mass index, tumor size, grade, nodal status, and receptor status, were related to metastatic patterns. Results: Ninety-five of 687 patients, (13.8%) developed metastases to bone (n=42) or visceral sites (n=53). Metastases to viscera occurred within five years, a latent period which was shorter than that for bone (P = 0.042). Significantly more women with visceral metastasis presented with grade 3 tumors compared with the bone and non-metastatic groups (P = 0.0002). There were 135/574 women (23.5%) with triple-negative breast cancer, who presented with lymph node involvement and visceral metastases (68.2% versus 24.3%; P = 0.033). Triple-negative tumors that metastasized to visceral sites were significantly larger (P = 0.007). Although the probability of developing a visceral metastasis within 10 years was higher among women with triple-negative tumors, this relationship was not influenced by increasing body mass index. Conclusions: For all breast cancer receptor subtypes, the probability of remaining distant metastasis-free was greater for brain and liver than for lung. The excess risk of metastatic spread to visceral organs in triple-negative breast cancers, even in the absence of positive nodes, was combined with the burden of larger and more advanced tumors. Impact: The reduced survival of breast cancer patients in rural areas may be explained by a high prevalence of triple-negative tumors with a propensity for visceral metastasis. Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A85.