Parasagittal biopsies are more important as part of an initial biopsy strategy than as part of a repeat biopsy strategy: observations from a unique population

Abstract

Comparing the yield of parasagittal biopsies during initial saturation biopsy to the yield during repeat saturation biopsy for detection of prostate cancer. Office-based saturation biopsy (24 cores) with periprostatic lidocaine block was performed in 139 consecutive men who had never previously undergone prostate biopsy. Indication for biopsy was elevated prostate-specific antigen >2.5 ng/dl. Biopsy specimens were obtained and marked by location for histological examination. Subanalysis of patients from this unique study was performed to compare the location of saturation biopsy cancer detection in these patients to a cohort of 100 patients who had previously undergone biopsy with nonmalignant findings. In the initial biopsy group, cancer was detected in 62/139 patients (44.6%). Breakdown of cancer location demonstrated unique parasagittal cancers in 9/62 patients (14.5%). Laterally base cancer was found exclusively in 22/62 patients (35.5%). For the repeat biopsy population, cancer was found in 25 patients (25%); no patients (0%) had exclusive parasagittal cancer. To our knowledge, this is the first study to demonstrate a difference in the location of positive cores between initial and repeat biopsy status. The exclusive parasagittal cancer detection rate decreases significantly in the repeat biopsy population when using the same biopsy method. Our findings support including traditional template parasagittal sampling of the prostate on first-time biopsy in addition to lateral cores typical of extended field biopsies for a total of 10–12 cores. However, parasagittal sampling adds negligible additional information in repeat biopsy; thus we recommend obtaining primarily laterally based cores for repeat biopsy.