Objective: To determine the capacity of PSA, tumor grade and local stage to predict the bone scintiscan findings in patients with newly diagnosed, untreated prostate cancer.
Methods: We analyzed the records of 189 patients with prostate cancer that had been seen at our institution from January, 1993 to September, 1995. PSA determination was performed prior to biopsy, local staging by DRE or transrectal US was done and they had a bone scintiscan before treatment.
Results: 21% of the patients had metastasis. Univariate analysis showed PSA (p < 0.001), tumor grade (p = 0.01) and local stage (p = 0.001) independently predicted the positive bone scintiscans. However, multivariate regression analysis showed tumor grade (rc = 0.05) or stage (rc = 0.07) did not increase the predictive value of PSA (rc = 0.22). The highest negative predictive value of PSA [95% (IC95 = 87.5%, 98.6%)] was obtained when 20 ng/ml was used as cutoff. Therefore 1.4% to 13.5% of the patients with bone metastasis could not have been diagnosed without scintigraphy.
Conclusion: Bone scintigraphy should be performed routinely to determine the extent of the lesion in patients with prostatic cancer, particularly in those patients that are likely to undergo radical treatment.