Utilidad de la fosfatasa alcalina ósea en la detección de metástasis óseas en cáncer de próstata

OBJECTIVES: To assess the clinical usefulness of bone-specific alkaline phosphatase (BAKP) to detect or rule out bone metastases in patients with prostate cancer. METHODS: Between November 2001 and July 2003 111 patients with the diagnosis of prostate adeno-carcinoma were evaluated to rule out bone metastases. Bone metastases were studied after clinical suspicion, PSA value higher than 10ng/ ml, or Gleason score higher than 7. Bone scan was used as detection test. Patients were tested for serum BAKP with a reference value equal or higher than 30 ng/ ml. The sensitivity, specilicity, positive predictive value and negative predictive value of BAKP were measured in comparison to bone scan as the gold standard. RESULTS: 111 patients with the diagnosis of prostate adenocarcinoma were evaluated to rule out bone metastases. Mean age was 69.70 years (50-83 years). Average B-AKP value was 29.28 ng/ Ml (9-56 ng/ ml). Bone scan was positive in 31 patients. Among these 31, 26 patients had positive BAKP and five negative. AP patients had negative bone scan. From this AP patients, B-AKP was positive in 17 and negative in 63. The sensitivity of the test was 83.8% The specificity was 78% Positive predictive value was 60% and negative predictive value was 92% CONCLUSIONS; Bone alkaline phosphatase is a greatly useful test for the study of patiente with prostate cancer in whom bone metastases are suspected either to confirm them or to rule out their presence.