What is the Best Number of Core to Improve Saturation Biopsy Detection Rate?

Abstract

Prostate core saturation biopsy (SB) is today considered in patients where clinical or biochemical hypothesis of prostate cancer (PCa) is still present after previous normal core biopsies. The technique rationale is to increase the detection rate (DT) both by increasing the number of cores for the pathologist, in order to obtain more tissue to be analyzed, and both by mapping regions that are not usually investigated with a standard or extended prostate biopsy. Moreover, the technique is not free from complications and today, one of the main controversies about SB is how many cores have to be taken in order to maintain high detection rate with low complication rate. Aim of the present retrospective study is to compare safety and DT of 3 different schemes of SB, performed with different number of cores.

Materials and Methods

We retrospectively reviewed the data of 106 patients who underwent SB from January 2003 to December 2008 at 2 urological divisions. SB was performed in all cases as a further biopsy because of biochemical and/or clinical hypothesis of PCa, in patients previously undergoing one or more baseline core biopsies. SB was performed under general anesthesia by 3 urologists in each division.

Core biopsies were obtained using a Boston Scientific TruPath 18G 15cm needle, in transrectal ultrasound-guided approach. All patients were submitted to a 32.core SB scheme. We compared the 32-core scheme with a 28 and a 24-core scheme, each one including peripheral, transitional and anterior prostatic portion biopsies.

End-points of the study were: DT and safety. Statistical analysis was carried out using chi-square test (p<0.05).

Results

Mean age was 65.4 (50–79) years, mean PSA at biopsy was 11.2 ng/ml (3.23–30) and mean number of previous biopsies was 1.5 (1–5).

Median value of cores positive for PCa in the 32, 28 and 24-core scheme was 2 (1–10), 2 (2–12) and 1.5 (0–11), respectively. Homogeneous distribution of positive cores was registered in all records, but in 3 areas (right base external, left base external, left transitional basal) the detection rate was very low (0–0.1%). PCa was found more frequently in base in median portion of left and right prostatic lobes. In the 32-core SB scheme, DT was 30.1 %, whereas in the 28 and 24-core SB scheme DT proved to be 28.7% and 29.1%, respectively. No statistical difference was found among the schemes in terms of detection rate (p>0.05). A Gleason score >7 was registered in 62.5% of cases.

As far as safety is concerned, 20 patients (19%) developed complications. In all cases neither hospitalization nor surgery were required and all patients were treated by medical therapy (e.g. indwelling catheterization, antibiotics).

Conclusions

SB after a previous standard core biopsy is a safe technique and increases DT of PCa. Although there is a propensity in increasing the number of core biopsies to obtain higher DT, our data suggests that DT does not increase when more than 24 cores are taken. Therefore, SB should be considered as second biopsy in patients with previous negative first standard core biopsy.