Significance of a new stratification of alkaline phosphatase and extent of disease in patients with prostate carcinoma with bone metastasis.

Bone is the most frequent site of metastatic prostate cancer and the prognosis of patients with bone metastasis is poor. The authors have investigated a semiquantitative system to evaluate bone metastatic lesions in terms of cancer-specific survival. Based on the extension of disease (EOD) grade proposed by Soloway and associates, a new EOD grading system obtained from bone scintigraphy alone and EOD score obtained from bone scintigraphy and alkaline phosphatase was studied in 164 patients with prostate cancer with metastatic bone involvement. In terms of a cancer-specific survival and prostate cancer death, both the new EOD grade and the EOD score were apparently superior to eight other items studied (age, medical score, gait disturbance, histologic grade, erythrocyte sedimentation rate, prostatic acid phosphatase, and alkaline phosphatase). Multivariate analysis revealed that the EOD score was better than the new EOD grade. This improvement was due to the elimination of false-positive or nonactive metastatic bone lesions on bone scintigraphy through the alkaline phosphatase evaluation.