Influence of the prostate volume, prostate specific antigen density and number of biopsy samples on prostate cancer detection.

Aim: Establish the main differences in the prostate volume, prostate specific antigen density (PSAD), number of biopsy samples in patients with primarily or rebiopsy detected prostate cancer.

Materials And Methods: In the 2007-2009 period, at the KCUS Urology Clinic, there were 379 TRUS guided prostate biopsies in 323 patients with known prostate volume. The total of 56 patients (17.3%) underwent the first rebiopsy, primarily due to precancerous lesions. The mean prostate volume, ranges of prostate size, PSAT, PSAD and the number of biopsy samples were analysed retrospectively, and the main characteristics in patients with primarily and rebiopsy diagnosed Pca were evaluated as well.

Results: The first biopsy cancer detection rate was 29.6% (112/379). The rebiopsy detection rate was 30.3%. There was no statistically significant difference in the prostate volume and the number of biopsy samples among the total number of patients with prostate cancer against the group with benign (suspected) findings. There was a higher Pca detection rate in patients with the prostate volume < 40 cm3 and 40-60 cm3, against the group with the prostate volume > 60 cm3. PSAD was significantly higher in patients with PCa (0.24 vs. 0.18; p = 0.013). The total of 27.2% of the patients with negative biopsy findings and 48% of the patients with diagnosed Pca had PSAD > 0.15. PSAD showed sensitivity and specificity in prostate cancer detection of 50% and 75%, with PPV of 48%. Furthermore, the patients with PSAD >0.15 had a higher Gleason score versus the patients with PSAD < 0.15 (6.7 +/- 2.4 vs. 5.9 +/- 1.7; p < 0.003). A comparison of the main characteristics in patients with primarily and rebiopsy detected prostate cancer gave a statistically significant difference only in the number of biopsy samples (10.9 vs. 14.1, p <.0000).

Conclusion: Patients with a smaller prostate volume, lower PSAD and a higher number of biopsy samples in rebiopsy have a higher chance of prostate cancer detection. PSAD carries a higher specificity in rebiopsy decision, and a higher PSAD is related to a higher Gleason score.