Comparison of insignificant cancer detection rates in prostatectomies performed following 6 and 12-core biopsy schemes U. Berber * , A. Haholu, I. Yilmaz, Z. Kucukodaci, D. Demirel * GATA HEH, Dept. of Pathology, Istanbul, Turkey Objective: Widespread use of extended biopsy protocols have increased the prostate cancer detection rates. Besides this improvement, whether detection of clinically insignificant cancer detection rates are increased by extended biopsy protocols is not well documented. In the study, we aimed to compare the rates of insignificant cancers found in prostatectomy specimens performed following 6 and 12-core biopsy protocols. Method: Retrospectively, we investigated the low volume/ low grade (LV/LG) prostate cancers in 160 prostatectomy specimens. Tumors volumes were calculated digitally as multiplying total tumor areas by 3 mm for average block thickness, and corrected for tissue shrinkage by multiplying a factor of 1.25. Results: Of the 160 prostatectomies, 54 were performed following sextant technique, and 106 were performed after 12-core protocol. Review of the H&E stained sections revealed 21 insignificant cancers. Number of LV/LG tumors found in 6 and 12-core groups were 3(5.6 %) and 18 (16.9 %), respectively. Conclusion: When compared to sextant technique, detection of LV/LG tumors were significantly raised in prostatectomies performed following 12-core protocol, and this increase points out the need for new approaches in patient management to avoid overtreatment after extended biopsy protocols.