Digital image analysis of the tissue surface areas of site-designated and bilaterally pooled prostate biopsies

Abstract

Initial reports about the length of bilaterally pooled biopsies showed alarming tissue loss compared to individual biopsies, but the current understanding of “noodle biopsies” and better embedding techniques may have improved their quality. Here, we implemented digital image analysis to study the differences in tissue surface areas between individual and pooled cores. Prostate biopsy reports from 1242 consecutive patients were reviewed. Urologist-dependent bias on the biopsy quality was eliminated by identifying four urologists who submitted equally individual and bilaterally pooled biopsies. Digital image analysis was applied to the tissue surface areas of 936 virtual slides containing 1440 biopsy cores (12 cores per patient x 120 patients) taken by the four urologists. The median (range) surface areas were 73.8 mm2 (40.1-102.5) for the site-designated (n=57) and 77.1 mm2 (49.5-119.2) for the bilaterally pooled biopsies (n=63) (p=0.19). For three urologists, the median surface areas were 69.5 mm2 (60.4-93.2), 75.5 mm2 (48.2-98.7) and 78.2 mm2 (47.1-92.7) for the site-designated and 79.2 mm2 (49.5-116.4), 69.3 mm2 (49.6-119.2) and 79.2 mm2 (55.1-96.7) for the pooled biopsies, respectively (p=0.58-0.75). For one urologist, the median surface area was marginally higher for the pooled biopsies, 68.1 mm2 (40.1-102.5) vs. 81.6 mm2 (62.7-108.8) (p=0.03). In conclusion, the histological yields of individual and pooled prostate biopsies were practically equal. The results should not be considered as a recommendation to increasingly submit unspecified bilateral cores but to encourage pathology laboratories to embed and cut all received prostate biopsies with special attention, regardless of submission type.