Prostate cancer detection with two sets of ten-core compared with two sets of sextant biopsies

To compare the cancer detection of two consecutive sets of prostate biopsies using either the sextant or the 10-core technique.

Ninety-one specimens after radical prostatectomy were used and consecutive sets of biopsies were performed ex vivo on each prostate after the operation. The sextant biopsies were taken paramedian and midlobular, three per side. For the 10-core biopsies, two cores per side from the lateral areas of the prostate were added. We developed a realistic simulation of a transrectal sonographic biopsy procedure.

In the first set of sextant biopsies, 55 prostate cancers (60.4%) were found; in the second set, 13 additional tumors were detected. Two consecutive sets of sextant biopsies thus found 68 tumors (74.7%). Using one 10-core biopsy led to cancer detection in 71 of the prostates (78%). A second 10-core biopsy revealed 11 additional tumors, for a cumulative cancer detection rate of 90.1%. We found that 9 (9.9%) of all the cancers were not diagnosed by two consecutive sets of this extended biopsy protocol. Eight of these cancers (88.9%) were clinically significant as determined by a tumor volume larger than 0.5 cm(3).

Although the 10-core protocol is far superior to the commonly used sextant protocol, a significant number of prostate cancers can still be found on a second similar set of prostate biopsies. Even after two consecutive sets of 10-core biopsies, approximately 10% of the prostate tumors remained undetected. Most of them were clinically significant.