Background: The osteolytic activity of metastases of prostate cancer was evaluated in relation to total body bone mineral content (TBBMC) and regional bone mineral content (RBMC).
Methods: Bone mass was determined by dual-energy X-ray absorptiometry (DXA). Tartrate-resistant acid phosphatase (TRAP) was measured as a biochemical marker of bone resorption.
Results: In 32 patients (mean age 72+/-4 years) compared with 32 controls (mean age 73+/-5 years), there were significant differences in TRAP (P < 0.0001), TBBMC (P < 0.0001), and RBMC in the pelvis (P < 0.0001), legs (P=0.0001), and trunk (P<0.05), but not in the arms and head (P=ns). In the overall group of subjects, the correlation between TBBMC and TRAP was r=-0.68, P < 0.0001. The correlations remained significant in the patient and control groups separately.
Conclusions: The loss of bone mass observed in patients with metastatic prostate cancer was caused mainly by the predominance of bone resorption in the osteoblastic metastases.