Breast Cancer Pathology, Receptor Status, and Patterns of Metastasis in a Rural Appalachian Population

Abstract

Breast cancer patients in rural Appalachia have a high prevalence of obesity and poverty, together with more triple-negative phenotypes. We reviewed clinical records for tumor receptor status and time to distant metastasis. Body mass index, tumor size, grade, nodal status, and receptor status were related to metastatic patterns. For 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). More women with visceral metastasis presented with grade 3 tumors compared with the bone and nonmetastatic 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 larger (P=0.007). Developing a visceral metastasis within 10 years was higher among women with triple-negative tumors. Across 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.