Predicting unilateral prostate cancer based on biopsy features: Implications for focal ablative therapy-results from the SEARCH database

Purpose: For men with low risk prostate cancer it was recently proposed that ablative treatment to the affected side may decrease morbidity, while maintaining good oncological outcomes. However, few studies have assessed the correlation between biopsy parameters and pathological outcome (unilateral vs bilateral disease). Materials and Methods: Using the Shared Equal Access Regional Cancer Hospital Database of men treated with radical prostatectomy at multiple equal access medical centers we retrospectively examined the records of 261 men with clinical stage T1c or T2a prostate cancer, prostate specific antigen less than 10 ng/ml, Gleason sum 6 or less and only 1 or 2 ipsilateral positive cores on at least sextant biopsy. We compared clinical characteristics between men with pathologically unilateral disease or less (pT2b or less) and men with pathologically bilateral disease or extraprostatic extension (pT2c or greater). To determine the significant predictors of pT2c or greater disease we used a multivariate logistic regression model. Results: Of the cohort of 261 men with low risk prostate cancer only 93 (35.1%) had unilateral or no evidence of disease following examination of radical prostatectomy specimens. Men with pathologically unilateral or less disease did not differ from those with bilateral or more advanced disease by age, prostate specific antigen, clinical stage, body mass index or number of positive biopsy cores (1 vs 2). On multivariate analysis no clinical feature was significantly related to pathologically unilateral or less vs bilateral or greater disease. Conclusions: The majority of men with low risk prostate cancer and 1 or 2 ipsilateral positive biopsy cores have pathologically bilateral disease. Therefore, strategies for unilateral treatment of prostate cancer are unlikely to be curative for these men.