PROSTATE CANCER DETECTION YIELD IN REPEATED BIOPSY IS INDEPENDENT OF THE DIAGNOSIS OF EARLIER BIOPSIES

Background. We analyzed data gathered from initial and repeated prostate biopsies at the University Hospital in Olomouc, Czech Republic. We evaluated the diagnostic yield of repeated transrectal ultrasound (TRUS) guided biopsies. We also assessed whether the result of the repeated biopsy depended on the benign diagnosis of the previous biopsy. Methods. From June 2006 till December 2008, the total of 794 men underwent a TRUS guided biopsy. The following parameters were recorded for each patient: age, total Prostatic Specific Antigen (PSA) level, free PSA level, digital rectal examination record, total prostate volume, and the histo-pathological evaluation. For patients undergoing a repeated biopsy, the histo-pathological result of the previous biopsy was also available, as well as the total number of previous biopsies and the time since the last biopsy. These data were analyzed using standard statistical methods. Results. Initial biopsy was positive for prostate cancer in 157 out of 566 men (27.7%). The total PSA level was confirmed to be a significant (P < 0.001) predictor of prostate cancer. The ratio of free PSA to total PSA (the so-called PSA index) was found to be significantly lower (P < 0.001) for patients suffering from adenocarcinoma. A total of 191 men underwent a repeated biopsy. The repeated biopsy was positive for adenocarcinoma in 39 cases (20.4%). Although this yield is lower, the significance is at the threshold (P = 0.04700). In the group of rebiopted men, total PSA level and PSA index were again significant (P = 0.0024 and P = 0.0015 respectively) predictive factors for prostate carcinoma. The diagnostic yield of repeated biopsy was assessed with respect to the most common types of the benign findings in the previous biopsy - adenomyomatous hyperplasia, inflammation, high grade prostatic intraepithelial neoplasia, and suspected adenocarcinoma. No significant difference in the diagnostic yield was found (P = 0.38431). Conclusions. Total PSA level and PSA index are the most significant precursors of adenocarcinoma in both initial and repeated biopsy. The histo-pathological result of a repeated biopsy was found to be independent of the type of benign diagnosis of the previous biopsy. A substantial number of prostate cancer is diagnosed in repeated biopsies which advocates for the indication of a repeated biopsy in case of a negative result of the initial one.