Relationship between BMD, osteocalcin, and bone alkaline phosphatase in pre- and postmenopausal women with advanced breast cancer

Objectives: In patients with advanced breast cancer (BC) direct bone resorption by lytic metastases, together with the action of local osteolytic factors, such as PTHrP, are the mechanisms causing malignancy-related hypercalcemia. Serum osteocalcin and bone alkaline phosphatase (BAP) are widely used in monitoring the response to therapy in patients with metastatic BC and progressive disease, and fracture risk identification has become an important aspect, especially in those who had undergone hormone replacement therapy. The aim of this study was to assess the relationship between osteocalcin, BAP, and BMD in pre- and postmenopausal women with metastatic BC. Materials/Methods: We studied retrospectively 37 patients (median age 51 years, range 34–74 years) with metastatic BC. There were 19 premenopausal (Group A), and 18 postmenopausal (Group B) women. Lumbar spine (L2–L4) BMD using DXA and bone formation markers osteocalcin and BAP were measured in all patients. Results: Baseline osteocalcin (26.0±7.1 vs. 25.2±8.5 ng/ mL, p=0.75) and BAP (27.4±11.1 vs. 29.6±8.8 U/L, p= 0.51) did not differ (Group A vs. B), and their serum levels were similar (p=NS) in the subgroup of patients reported in the Table. In Group A there was no correlation between BMD and both osteocalcin (R=-0.005, p=098) and BAP (R=-0.15, p=0.54), while in Group B a significant relationship between osteocalcin and age (R=0.51, p=0.023), BAP (R=0.55, p=0.013), and BMD (R=-0.47, p=0.041) was found. Conclusions: In postmenopausal women with advanced BC both BMD and bone formation markers measurements are useful in identifying the risk of disease progression.