Objectives: To evaluate the behavior of bone alkaline phosphatase (BAP) after androgen deprivation therapy in patients with prostate cancer.
Methods: BAP was determined in the serum of 35 patients with nonmetastatic prostate cancer before maximal androgen blockade. During 5 years of follow-up, BAP was determined annually. A subset of 36 patients who underwent radical prostatectomy as the only treatment for prostate cancer was selected as a control group.
Results: The mean pretreatment BAP serum concentration was similar in both groups (10.8 and 10.4 ng/mL, P >0.05). However, after 5 years, the mean BAP serum concentration increased 64.8% in the study group (from 10.8 to 17.6 ng/mL, P < 0.001); it remained stable in the control group (from 10.4 to 10.4 ng/mL). The increase of serum BAP in patients receiving androgen deprivation was 32.4% during the first year (from 10.8 to 14.3 ng/ml), 16.7% during the second (from 14.3 to 16.1 ng/mL), 7.4% during the third (from 16.1 to 16.9 ng/mL), 5.5% during the fourth (from 16.9 to 17.3 ng/mL), and 2.8% during the fifth year (from 17.3 to 17.6 ng/mL).
Conclusions: Androgen deprivation produces an increase in the BAP serum concentration. A major increase seems to be produced during the first year of follow-up and thereafter this increase is reduced around 50% annually.