Prostate Specific Antigen and Bone Scan

Abstract

Prostate specific antigen (PSA) is known to be the most sensi tive marker available for monitoring the progression of pros tate cancer and the response to therapy. PSA concentrations tend to increase with the advancing clinical stage of prostate cancer. To assess the role of PSA in detecting skeletal metastases, PSA levels were correlated retrospectively with 99mTc MDP bone scan findings in 35 known prostate cancer pa tients. The cutoff level was set at 10 ng/ml. Of the 35 bone scans, 24 demonstrated metastatic bone disease. Twenty of the 24 had serum PSA values of > 10 ng/ml (13-800 ng/ml). Of the 11 patients with negative bone scans, 2 had PSA values >10 ng/ml. The PSA level had a direct correlation with the incidence of positive bone scan (p < 0.001). The sensitivity of the marker was 83.3% and its specificity was 81.8%. Thus, serum PSA level is a useful biochemical tumor marker that can help in the assessment of skeletal metastases of prostate cancer patients during their follow-up. When used in combi nation with scintigraphic bone findings, a more accurate clini cal picture of the patient is obtained.