Extent of disease based on initial bone scan: important prognostic predictor for patients with metastatic prostatic cancer. Experience from the Scandinavian Prostatic Cancer Group Study No. 2 (SPCG-2).

The skeleton is the most frequent site of metastases from prostate cancer. Quantitation of the amount of tumor burden has a great prognostic value and is of importance for clinical trials. The present study reviews 194 bone scans from the SPCG-2 study which consisted of 294 patients entered into a randomized prospective multicenter trial, comparing total androgen suppression with standard treatment in patients with metastatic prostatic cancer (orchiectomy plus cyproterone acetate vs. orchiectomy plus placebo). Evaluation of the initial bone scans based on the extension of the disease (EOD) as proposed by Soloway and associates gives a convenient stratification of the patients. With regard to time to progression and cancer-related as well as overall survival, this EOD grading system had a significant prognostic value (p < 0.001). There was no statistical difference between the two treatment arms in the different categories of the EOD grading system with regard to time to progression and time to death. By analyzing exclusively the subgroup of patients with minimal disease (EOD I) and good performance status (WHO score 0), there was a nonsignificant trend toward a better 2-year progression-free survival as well as a better 2-year cancer-related survival for those who were subjected to total androgen suppression as compared with the patients subjected to the standard treatment (orchiectomy).