Topography of the prostate cancer at the initial and next saturation biopsy
Article published in Urologia Polska 2008/61/Supl. 1.

authors

Adam Gołąb, Michał Soczawa, Marcin Słojewski, Bartłomiej Gliniewicz, Andrzej Sikorski

Klinika Urologii PAM w Szczecinie

summary

Introduction.

Saturation biopsy (SB) is an acknowledged method of diagnosis in prostate cancer especially in males undergoing repeated evaluation. Only few reports provided data on SB performed as an initial investigation. We believe that more profound research in this direction would allow elaboration of optimal technique, achieve better results of cancer detection, and in consequence, would lead to adaptation of SB also as an initial investigation.

Objectives.

The aim of the study was to evaluate topography of the prostate cancer diagnosed at initial and repeated saturation biopsy with regard to practical aspects.

Materials and methods.

Between 2004 and 2007 four hundred seventeen saturation biopsy of the prostate were performed, including 306 initial and 111 repeated biopsies following limited core biopsies (6-12) or SBs. The prostate cancer was diagnosed in 117 patients (28.0%) in the whole group. Mean age of the studied males was 67 years, mean PSA value – 10.64 ng/ml, and mean prostate volume was 63.7 cm3. The rate of the initial studies was 2.63 in the repeated investigations. At the initial SB 18 samples covering the entire peripheral prostate zone (according to McNeal), and at the repeated SB the above mentioned scheme was extended of 6 additional biopsies within the transition zone (total 24). Statistical analysis was performed with application of Fisher and Ward tests, and Spearman’s rank correlation coefficient.

Results.

In the initial SB the cancer was located mainly in the peripheral parts and in the vicinity of the prostate apex – up to 34% of positive cores; the lowest rates were found at the prostate base and in the midline – up to 22% of positive cores. A similar topographic scheme of the prostate cancer, if consider percentage of positive cores was found at the repeated SB. The significant differences were found for the apex, were in the repeat biopsy cancer located proportionally rarely than in another part of the prostate (p<0.002). A similar but statistically insignificant tendency was found for the periapical zone. Attention was drawn by high rates of positive biopsies within the transition zone at the repeated biopsy (up to 16%) that was comparable with the results obtained for the peripheral zone. The correlation tests revealed that in the same patient specific location of the cancer frequently coexisted with other site, usually adjacent to the first lesion. For the chosen prostatic zones the frequency of the phenomenon reached the statistical significance (p<0.01). In the initial SB these

areas included: the external part of the peripheral zone and midline part vs basal. In the repeated SB the cancer coexisted in the biopsies from the external part of the peripheral zone and bilaterally at various sites that justified recognition of multifocal prostate cancer. No significant coexistence of cancer sites located within peripheral and transition zones were found.

Coexistence of the various sites of the prostate cancer allows possibility to limit the core numbers at SB without affecting the overall detection of the tumor.

Conclusions.

1. Prostate cancer detected by SB is mainly located in the external part of the peripheral zone. In the initial SB cancer is also frequent found in the apex. In the repeated SB prostate cancers tend to be multifocal. 2. Biopsy in the transition zone is necessary at the repeated investigation due to high rates of isolated cancers detected in that area. 3. The core numbers in SB may be limited without affecting the detection rates of the prostate cancer.