BIOCHEMICAL MARKERS OF BONE TURNOVER IN WOMEN WITH SURGICALLY TREATEDCARCINOMA OF THE BREAST

Biochemical markers of bone turnover were measured in fasting urine an d blood samples obtained from 38 postmenopausal women with previous su rgical treatment of breast cancer combined with adjuvant chemotherapy, tamoxifen, or placebo. Significantly elevated urinary pyridinoline as nmol mmol-1 creatinine (47.5 and 42.5 in tamoxifen and placebo treate d patients compared with 26.3 in normal controls, both P < 0.00 1) and deoxypyridinoline (11.9 and 10.5 compared with 6.3, P<0.001 and P=0.0 02 respectively) were found with unchanged urinary hydroxyproline, ser um alkaline phosphatase and procollagen I carboxyterminal peptide (PIC P). These findings suggest enhanced bone resorption resulting from the humoral osteoclast activating effect of the previous breast cancer or underlying carcinoma recurrence. Alternatively the raised pyridinium excretion might indicate an altered crosslinking composition of bone c ollagen. No specific effect on bone metabolism was found with tamoxife n treatment as all measured parameters were similar in both tamoxifen ex-users and non-users. This confirmed the safety of tamoxifen therapy with respect to bone.