925 LIMITED PREDICTIVE VALUES OF PROSTATE BIOPSY AND MRI TO THE LATERALITY OF CLINICALLY LOCALIZED PROSTATE CANCER

Article Outline

• INTRODUCTION AND OBJECTIVES
• METHODS
• RESULTS
• CONCLUSIONS
• Copyright

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INTRODUCTION AND OBJECTIVES 

We usually rely on laterality prediction based on prostate needle biopsy (PBx) and MRI, when we plan nerve-sparing radical prostatectomy. Recently some investigators have suggested that PBx unilaterality is the most important indication of focal therapy for low risk prostate cancer patient. Thus we evaluated whether preoperative PBx and MRI can predict the laterality of final specimen pathology after radical prostatectomy.

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METHODS 

From January 2001 to March 2009, among 1007 consecutive radical prostatectomy cases, 574 cases which had PBx at least 12 cores and preoperative prostate MRI with complete medical data were enrolled in this study. We analyzed the clinicopathologic data with laterality based on PBx and MRI. Unilateral cases in PBx which had undetectable or agreed laterality in MRI were regarded as unilaterality in combination of PBx and MRI. Cohen′s kappa (κ) was used to measure the agreement between laterality data.

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RESULTS 

There were total 316 (65.0%) unilateral cancers in PBx whereas 139 (23.2%) cases in final specimen pathology. MRI resulted in 119 (20.7%) undetected cancers and 205 (35.7%) unilateral cancers. Cancer laterality of final specimen pathology had only fair agreements with PBx (κ=0.286) and MRI (κ=0.200, except undetectable cancer, n=455). Even though both PBx and MRI results were combined, κ remained at 0.291. Similarly, these trends stood still in low-risk cases (prostate specific antigen < 10ng/ml, clinical stage ≤ T2a, and biopsy Gleason score ≤ 6)(Table 1). Furthermore, even when PBx unilaterality was re-defined only in cases with single or ≤ 2 positive cores, positive predictive values of unilaterality were still low. (κ=0.239 and 0.306, respectively)

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CONCLUSIONS 

Preoperative PBx, MRI and there combination have only a fair correlation with the laterality of clinically localized prostate cancer even in low-risk cases. One should recognize this when planning nerve-sparing surgery, and potentially for focal therapy of prostate cancer.