Objective: To analyze the influence of prostatic intra-epithelial neoplasia (PIN) on serum total PSA levels and free PSA percentage.
Material and methods: Total and free PSA concentrations (IRMA Tandem and Tandem free PSA, Hybritech Inc) were determined in 349 patients with normal DRE and PSA greater than 4 ng/ml, undergoing prostatic biopsy by sextant and in 81 patients with prostate cancer in clinical stage T1c N0 M0 undergoing radical prostatectomy. In the group of patients undergoing prostatic biopsy, benign hyperplasia was diagnosed in 284 (81.6%) patients, 234 (82.4%) were PIN free, 41 (14.4%) with low grade PIN and 9 (3.2%) with high grade PIN. Cancer was diagnosed in 65 patients (18.6%), 30 of whom (46.2%) had associated high grade PIN. High grade PIN was detected in 62 (76.5%) patients in the group undergoing radical prostatectomy.
Results: No statistically significant differences were detected among total PSA and free PSA percentage serum concentrations relative to the detection of associated PIN, regardless of its degree, in patients undergoing prostatic biopsy. Cancer detection was the single most significant contributing variable. In patients undergoing radical prostatectomy, high degree PIN did not influence significantly. The greatest contribution in this group was the pathological stage.
Conclusions: PSA serum concentration and PSA percentage are not influenced by the existence of PIN. High degree PIN is strongly associated to cancer. Accordingly, repeat biopsies are warranted in any patient presenting such lesions.