Clinicopathological strategies to identify contralateral prostate cancer involvement in potential candidates for focal therapy.

OBJECTIVE: To identify the magnitude and possible predictors of contralateral lobe involvement and contralateral extraprostatic extension (EPE) in prostatic biopsy-defined localized unilateral cancers. PATIENTS AND METHODS: Between January 2005 and August 2009, 1861 patients underwent robotic-assisted radical prostatectomy at the authors' institution. A total of 1114 had unilateral disease on preoperative biopsy. Final histopathology reports of these patients were reviewed. RESULTS: Of the 1114 patients with unilateral disease on biopsy, 867 (77.9%) had contralateral or bilateral disease on final histopathology. EPE was found in 132 patients (11.9%). Twenty patients (1.8%) had contralateral EPE involvement. High-grade prostatic intraepithelial neoplasm (HGPIN) on biopsy was the significant predictor of contralateral lobe involvement on both univariate (P = .02; odds ratio [OR] = 1.791) and multivariate analysis (P = .004; OR = 2.677). Clinical stage T2 was the significant predictor of contralateral EPE on both univariate (P = .012; OR = 5.250) and multivariate analysis (P = .007; OR = 8.656). CONCLUSION: HGPIN on biopsy significantly predicts for contralateral lobe involvement and should be considered an exclusion criterion for focal therapy in prostate cancer patients. Patients with palpable tumor on digital rectal examination should be advised in favor of radical treatment as these patients may harbor more aggressive tumors involving the contralateral side despite the biopsy findings