Biochemical markers for the detection of bone metastasis in patients with prostate cancer: diagnostic efficacy and the effect of hormonal therapy

In the present study, we investigated the diagnostic effectiveness of biochemical markers of bone turnover for the detection of bone metastasis from prostate cancer and changes in the levels of these markers caused by hormonal therapy. Ninety-five patients with prostate cancer were divided into one of three groups: 26 patients with bone metastasis (BM(+)), 35 patients without bone metastasis on nonhormonal therapy (BM(-)HT(-)) and 34 patients without bone metastasis on hormonal therapy (BM(-)HT(+)). All patients in the BM(+) group had received hormonal therapy. Serum or urinary levels of the following biochemical markers of bone turnover were examined: bone-specific alkaline phosphatase (B-ALP), osteocalcin (OC), type I procoIlagen C-propeptide (PICP), type I collagen cross-linked C-telopeptide (ICTP), C-telopeptide fragment (CTx), N-telopeptide fragment (NTx), total pyridinoline (T-Pyr), total deoxypyridinoline (T-D-Pyr) and free deoxypyridinoline (F-D-Pyr). The BM(+) group showed significantly higher values than the BM(-)HT(-) group for B-ALP, PICP, NTx, CTx, T-Pyr, T-D-Pyr, and F-D-Pyr. Compared with the BM(-)HT(+) group, the BM(-) group showed significantly higher values for B-ALP, ICTP, NTx, T-Pyr and T-D-Pyr. The levels of B-ALP, NTx, CTx, T-D-Pyr and F-D-Pyr were significantly different between the BM(-)HT(-) and BM(-)HT(+) groups. All markers, except OC and CTx, significantly were correlated with the extent of bone metastasis on bone scintigraphy. Of all markers, receiver operating characteristic (ROC) analyses revealed B-ALP and F-D-Pyr to be the most sensitive and specific for differentiation between the BM(+) and BM(-)HT(-) groups with regard to bone formation and resorption. respectively. In contrast, B-ALP and ICTP were most sensitive and specific for differentiation between the BM(+) and BM(-)HT(+) groups. The results suggest that hormonal therapy greatly affects the efficacy of PICP, CTx and F-D-Pyr in the diagnosis of bone metastasis, whereas its effects on ICTP are small. Although bone metabolic markers would be useful in the diagnosis of bone metastasis from prostate cancer, the effects of hormonal therapy on bone metabolism should be kept in mind in their evaluation.