ABSTRACT
Aim: In this paper, we present a prospective observational study, which determines the incidence of bone metastases and its correlation with hormonal receptors (estrogen receptor [ER]/progesterone receptor [PR]) and human epidermal growth factor receptor 2 (HER2) in breast cancer. Materials and Methods: From October of 2015 to July 2017, 262 patients were eligible for the study, of which 98 patients presented/developed bone metastases. ER/PR and HER2 receptor status were determined, and bone scintigraphy with a technetium-99 m was carried out on each patient during the study. Results: The incidence rate of bone metastases as found in this study was 25.25%, and the mean and median age at diagnosis were 47.23 and 46, respectively (age range = 28–80). Bone metastases were more prevalent in ER-positive tumors (P = 0.043), tumors with lymph node positivity (P = 0.002), and lower grade tumors (P = 0.002), whereas visceral metastases were more common with ER-tumors (P = 0.005), tumors with higher grade (P = 0.012), and tumors with lymph node positivity (P = 0.034). In this study cohort, the spine and pelvis were the most commonly involved subsites of bone metastases (P < 0.001). Conclusion: This study demonstrates that the metastatic patterns in breast cancer strongly correlate with various breast cancer subtypes, mainly designated by ER, PR, and HER2. Hormone receptor-positive tumors show a predilection for bones as the first site of relapse compared to hormone-receptor-negative tumors which have a proclivity to develop as visceral metastases.