Does site specific labeling of sextant biopsy cores predict the site of extracapsular extension in radical prostatectomy surgical specimen?

Purpose: We determine whether site specific labeling of sextant prostate bi opsy cores predicts the site of extracapsular extension in a radical prosta tectomy specimen, thereby justifying increased cost of pathological evaluat ion. Materials and Methods: Between January 1994 and December 1997, 407 radical prostatectomies were performed at our institution by a single surgeon (H. L .). Surgical specimens showing extracapsular extension were examined by a s ingle pathologist (J. M.) to identify the site of extension; Several differ ent methods of submitting transrectal ultrasound guided biopsy cores were u sed since the majority of cases did not undergo biopsy at our institution. In 243 cases sextant biopsies were labeled right versus left. Of these case s 103 specimen cores were individually labeled. The ability of the positive biopsy core location to predict the location of extracapsular extension in the surgical specimen was determined. Univariate and multivariate logistic regression analyses were performed to assess the ability of biopsy core ch aracteristics, including Gleason score, percentage of cancer in the core, c ore location and number of positive cores in the specimen, to predict the s ite of extracapsular extension. A similar analysis was performed for the 24 3 cases with right versus left core labeling. Results: The positive predictive value was 8.9 +/- 2.2% for a single positi ve core to identify the location of extracapsular extension correctly in th e individually labeled core cases. The absence of cancer in a sextant biops y had a negative predictive value of 96.9 +/- 1.4%. The overall sensitivity was 59.4 +/- 3.8% for a positive biopsy core. In the right versus left cor e cases the positive predictive value was 12.9 +/- 3.0% with a sensitivity of 85.1 +/- 3.2%. In an individual core Gleason score 8 or greater and/or c ancer in more than 50% of tissue enhanced the positive predictive value but not to a clinically useful level. Multivariate logistic regression identif ied Gleason score, number of positive ipsilateral cores and base position o f the positive biopsy as the mast predictive variables for the site of extr acapsular extension. Conclusions: When submitting biopsy specimens by individually labeled care or right versus left core, the positive predictive value of an individual p ositive core for the location of extracapsular extension is not sufficient to guide the surgical decision to spare or excise a neurovascular bundle. T herefore, the clinical information provided by individually labeled or righ t versus left core labeling does not justify the increased associated costs .