Prostate volume index and chronic inflammation of the prostate type IV with respect to the risk of prostate cancer.

ABSTRACT

BACKGROUND: Benign prostatic hyperplasia and prostate cancer (PCA) alter the normal growth patterns of zonal anatomy with changes of prostate volume (PV). Chronic inflammatory infiltrates (CII) type IV are the most common non-cancer diagnosis of the prostate after biopsy. OBJECTIVE: To evaluate associations of both PV index (PVI), i.e. the ratio of transitional zone volume (TZV) to peripheral zone volume (PZV), and CII with PCA in patients undergoing biopsy. SUBJECTS AND METHODS: Between January 2007 and December 2008, 268 consecutive patients who underwent prostate biopsy were retrospectively evaluated. PV and TZV were measured by transrectal ultrasound. PZV was computed by subtracting the PV from the TZV. CII were evaluated according to standard criteria. Significant associations of PVI and the presence of CII (CII+) with PCA risk were assessed by statistical methods. RESULTS AND LIMITATIONS: We evaluated 251 patients after excluding cases with painful rectal examinations, prostate-specific antigen (PSA) >20 µg/ml and metastases. The PCA detection rate was 41.1%. PVI was a negative independent predictor of PCA. A PVI ≤1.0 was directly [odds ratio (OR) = 2.36] associated with PCA, which was detected more frequently in patients with a PVI ≤1.0 (29.1%) than in those with a PVI >1.0 (11.9%). CII+ was inversely (OR = 0.57) and independently associated with PCA, which was detected less frequently in cases with CII (9.9%) than in those without CII (21.1%). Potential study limitations might relate to the fact that PV was not measured by prostatectomy specimens and there was PSA confounding for CII and PCA. CONCLUSIONS: Low values of PVI are directly associated with risk of PCA, which was almost 2.5 times higher in patients with a PVI ≤1.0. The PVI might be an effective parameter for clustering patients at risk of PCA. CII+ was inversely associated with risk of PCA and decreased the probability of detecting PCA by 43%. The role of the PVI and CII in PCA carcinogenesis needs further research.