Previous studies from this institution have shown that in untreated stage A prostate cancer when 5 per cent of the specimen or less was involved by tumor (stage A1) only 2 per cent of the patients had progression at 4 years. Of the specimens with greater than 5 per cent cancer (stage A2) 33 per cent had progression at 4 years. More recently, we have shown that 16 per cent of the men with stage A1 disease who remained at risk for 8 years or longer after diagnosis had progression of disease despite a small percentage of the specimen involved by tumor. To address whether the actual volume of tumor resected may be a better predictor of progression than the percentage of the specimen involved by tumor the data from these studies were re-evaluated. We demonstrated that at 4 and 8 years of followup the percentage of the specimen and resected tumor volume were strongly associated with tumor progression, with the percentage of the specimen showing a stronger association especially at 4 years. Our study reaffirms the use of the percentage of resected tissue involved by tumor as a means to distinguish between stages A1 and A2 prostate cancer. Although at 8 years the distinction between stages A1 and A2 disease is blurred, this staging classification still is useful to identify those tumors with a relatively indolent course and a minimal short-term risk of progression from those that are more aggressive.
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