Aim of the study: To develop indications for repeat biopsy in patients with suspected prostate cancer and first negative biopsy.
Materials and methods: 148 consecutive patients, submitted to two or more biopsies for suspected prostate cancer, were extracted from our database on prostatic diseases. Patients were stratified according to the results of the last biopsy (benign or carcinoma) considering the results of the first and of the last biopsy when more than two biopsies had been performed. PSA velocity was calculated when the interval between PSA obtained before the initial and the final biopsy was at least 6 months; PSA velocities were annualized and absolute changes between the two groups were analyzed.
Results: Prostatic carcinoma was detected in 60 of the 148 patients (40.5%), including 19 of 41 (46.4%) with prostatic intraepithelial neoplasia (PIN) and 45 of 107 (42.1%) with normal tissue or prostatic epithelial atrophia on initial biopsy. 20% of patients (4 of 20) with low-grade PIN and 71.1% (15 of 21) with high-grade PIN had cancer at repeat biopsy. The mean PSA value of patients with carcinoma on the repeat biopsy was higher than that of patients without carcinoma (13.3 vs. 10.7 ng/ml). However, this difference was not statistically significant (p = 0.37). Mean PSA velocity increased for patients with a final diagnosis of carcinoma versus those without evidence of carcinoma (+0.3 vs. +1.4 ng/ml/year); this difference was statistically significant (p = 0.002).
Conclusions: According to these results, patients with either PIN II-III, or high PSA and PIN I on initial biopsy, and/or with elevated PSA velocity (more than 1 ng/ml/year) should undergo repeat prostate needle biopsy, being at high risk of prostate carcinoma.