The Flare in Serum Alkaline Phosphatase Activity After Orchiectomy: A Valuable Negative Prognostic Index for Progression-Free Survival in Prostatic Carcinoma

Abstract

Purpose We determined whether an early flare in serum alkaline phosphatase activity after orchiectomy was of prognostic value for progression-free survival in patients with advanced prostatic carcinoma. Materials and Methods A retrospective analysis of a data base from a Dutch multicenter study on prostatic carcinoma was done to determine the prognostic value of a flare in alkaline phosphatase activity after orchiectomy in 112 patients with metastatic (75 percent) or locally advanced (25 percent) disease. Cox's proportional hazards models and Kaplan-Meier survival curves were used. Results Of the patients 50 percent had initially increased alkaline phosphatase levels and a flare in activity was demonstrated in 87 percent 2 to 4 weeks after orchiectomy. The prostate specific antigen nadir (cutoff 4 ng./ml.) 6 months after orchiectomy was of significant prognostic value for progression-free survival. A flare in alkaline phosphatase activity after orchiectomy demonstrated an early significant prognostic value for progression-free survival, independent of the serum alkaline phosphatase activity. Conclusions The simplicity, ready availability and cost-effectiveness of serum alkaline phosphatase activity as a prognostic index render it attractive to the clinician, particularly early in the course of prostatic carcinoma. Measuring the flare in alkaline phosphatase activity within 1 month of orchiectomy may permit early identification of patients in whom the disease is likely to progress rapidly and who would potentially benefit from aggressive treatment.