Ability of Core Biopsies to Predict Extracapsular Extension of Prostate Cancer

Park, Soo Whan; Park, Jong Yeon; Ahn, Hanjong

Abstract

PURPOSE: To assess the ability of multiple variables to predict the extracapsular extension and lateralities of the extension on ten-core prostate needle biopsies.
MATERIALS AND METHODS
Eighty-five ten-core prostate biopsies and corresponding radical prostatectomy specimens were studied. Using univariate and multivariate regression analyses, variables, such as Gleason score, preoperative PSA, bilaterality of cancer, number of positive cores, total length of cancer, maximum length and percent of cancer on one core and maximum percent of cancer on one site were determined for their prediction of extracapsular extension.
RESULTS
Thirty-seven of the 85 patients (44%) showed extracapsular extension. In a univariate analysis, all variables, with the exception of the PSA, were significant. The number of positive cores was the only independent predictive factor in a multivariate analysis (p=0.0007). Nineteen (39.6%) of the 48 unilateral cancers cases on biopsy showed ipsilateral extracapsular extension, including 3 bilateral extensions on prostatectomy specimens. Significant differences in the Gleason score and number of positive cores were noted between organ confined and extracapsular tumors on the prostatectomy specimens. Among 37 bilateral cancers on biopsy, the probability of organ confined, unilateral extracapsular and bilateral extracapsular diseases were 51, 16 and 32%, respectively. The number of positive cores had a significant impact on the extension of tumors, with a dominant number of positive cores on the ipsilateral side.
CONCLUSIONS
The number of positive cores is the most important predictive factor for the extracapsular extension. The laterality of the extracapsular extension can be predicted by the laterality and dominance of positive cores on biopsies.