Prediction of Radial Distance of Extraprostatic Extension From Pretherapy Factors

Purpose: Extraprostatic extension (EPE) of tumor conveys an adverse prognosis in early-stage prostate cancer. Previous studies reported on the linear and radial distance of EPE (EPEr) as measured from the prostate edge. In this study, the correlation of the EPEr from a large whole mount prostatectomy series was determined with respect to the needle biopsy and prostatectomy specimen findings. Methods and Materials: In a 24-month period, 404 patients underwent radical prostatectomy and the specimens were whole mounted. The preoperative records, biopsy findings, and EPEr from these specimens were evaluated. Results: The range of the EPEr distance was 0.0-5.7 mm. A three-category model was used that included 283 patients (70%) with no EPE, 59 (15%) with "near EPE" (range, 0.01-0.59 mm), and 62 (15%) with "far EPE" (≥0.6 mm). Univariate analysis revealed that patient age and prostate volume did not correlate with EPEr, in contrast to all other factors evaluated. Multivariate analysis identified the preoperative serum prostate-specific antigen, the percentage of cancer in the biopsy cores, and clinical tumor stage as significant. However, the Gleason score was not associated with the EPEr. Greater discrimination was possible in estimating the probability of extension in the "near" category than in the "far" category. Conclusion: EPEr is associated with the preoperative prostate-specific antigen level, percentage of cancer in the biopsy cores, and clinical tumor stage. These data might be useful in planning local therapies for prostate cancer, but additional studies identifying factors associated with EPEr beyond 3-5 mm could have relevance regarding the appropriate radiotherapeutic management strategies.