[Indication of repeat prostatic biopsy following previous negative findings]

Many men with clinically suspicious findings would not be diagnosed to have prostate cancer. Establishing criteria for indicating repeat biopsy is imperative for early detection of prostate cancer.

Eighty-one patients underwent repeat prostatic biopsies under sonographic guidance at Kitasato University Hospital between March 1992 and October 1996. Clinicopathological parameters such as age, prostate specific antigen (PSA), PSA adjusted for transition zone volume (PSAT), PSA density (PSAD), PSA velocity, transition zone volume, prostatic volume, rectal findings, ultrasound findings and initial biopsy histology were compared with the results of repeat biopsy for searching for possible predictors of positive biopsy.

Cancer was confirmed in 14 patients (17.3%), 10 patients by the second biopsy (15.4%, 10/65) and 4 patients by the third biopsy (28.6%, 4/14). No cancer was found at the 4th or more biopsies. Twelve (85.7%) of these patients had prostatic volume less than 40 cm3. Univariate analysis indicated PSAT, PSAD, transition zone volume and prostatic volume to be more frequent in men with positive biopsies (p < 0.05). But multivariate logistic regression analysis failed to identify any significant predictors of positive results in repeat biopsies.

No clinicopathological parameters could reliably predict repeat biopsy findings. One or 2 additional sets of biopsies is recommended based on clinical judgement (symptoms, life expectancy, small glands < or = 40 cm3 etc.) for the purpose of early detection of prostate cancer in patients with previously negative biopsy but still with suspicious findings in consideration of approximately 20% false negative rates by the initial biopsy.