The diagnosis value of BAP and PSA in prostate cancer with bone metastases was studied and its application in the classification of bone metastases was investigated. 68 patients of prostate cancer undertook bone scintigraphy

and according to the result they were divided into 2 groups

with and without bone metastases. Furthermore the bone scan results were divided into 4 grades accoeding to Soloway standard. BAP and PSA tests were done in all patients and the correlation was calculated among various groups. Relation was studied between BAP and bone metastases grade. The result showed a positive correlation between BAP and bone metastases grade (r=1.1083

P<0.01)

while PSA only showed significant difference between M0 and M1—M3. The best value of BAP for prostate cancer metastases is 25—35 u/L

because the positive predictive value was 96.6% and negative predictive value was 75%. When using BAP in 35 u/L and PSA in 20 ng/mL

the positive predictive value was 97.5%. When using BAP in 25 u/L and PSA in 20 ng/mL

the negative predictive value was 73.9%. We can conclude that BAP is more effective in predicting bone metastases in prostate cancer than PSA

and has more diagnosis value in the grading of metastases. And the combination of BAP and PSA can increase the positive predictive value of bone metastases of prostate cancer.