The serial technetium 99 T DIAGNOSIS approximately 40% of prostate cancer A patients have metastatic disease' and 84% of patients with prostatic carcinoma will have bone involvement at autopsy.* Technetium 99m-labeled methylene diphosphonate (99mTc-MDP) bone scans have become a standard method of staging and monitoring prostate c a n~e r .~ Although several investigator^^-^ attempted to objectively quantify isotope uptake in individual scans, the differences in isotope activity, scanning equipment, and computer programs have frustrated these efforts. Efforts at computerizing the interpretation of bone scans to remove viewer bias have not gained widespread use. However, use of bone scans as a stratification variable for protocols involving advanced prostate cancer has more recently been appreciated. Ishikawa et a1. ' suggested that the absolute number of discrete bone lesions could be a stratification variable. The Southwest Oncology Group ( SWOG)9 reported that involvement of axial versus axial plus appendicular skeleton served the same purpose.To better define the natural history of the osseous metastatic process we analyzed the serial bone scans of 76 patients with advanced prostate cancer. Particular attention was directed to the predictive value of the initial From the Division

In an effort to determine the effect of cytoreductive surgery on the metastatic process, MAT-LyLu flank tumors were excised from Copenhagen x Fischer rats and the effects of this surgery on metastatic lung lesions were observed. Cytoreduction resulted in a decrease in lung lesions (P less than 0.05). Adjuvant cyclophosphamide (CTX) further enhanced this beneficial effect. A concurrent increase in the helper/suppressor ratios suggested that this beneficial response might be mediated by the host's immune response.