Objectives: A prostate biopsy data base derived from patients referred to private practice urologists was analyzed for the cancer diagnosis rates of the "initial" biopsy and the repeated biopsy performed within 1 year for those patients with a noncancer diagnosis.
Methods: A retrospective analysis assessed 132,426 prostate biopsies received and processed by a single pathology laboratory between March 1994 and September 1998; none had had a previous biopsy processed at this laboratory. Prostate cancer was diagnosed in 50,521 of the patients (38.2%). The remaining 81,905 patients (61.8%) had a noncancer diagnosis of either no evidence of malignancy (NEM), high-grade prostatic intraepithelial neoplasia (HGPIN), small acinar glands suspicious for cancer (suspicious), or suspicious with HGPIN (Susp-HGPIN). We identified 6380 (7.8%) of these "noncancer" patients who underwent a repeated biopsy within 1 year.
Results: The incidence of NEM, HGPIN, suspicious, and Susp-HGPIN biopsy diagnoses in the "noncancer" patients (81,905) was 55.3%, 3.7%, 2.5%, and 0.3%, respectively. The rate at which these "noncancer" patients (81,905) underwent a repeated biopsy was 4.8% for patients with a diagnosis of NEM, 26.6% for HGPIN, 40.4% for suspicious, and 47.5% for Susp-HGPIN. The overall cancer diagnosis rate in the repeated biopsy patient sample (6380) was 25.7%. When stratified by the initial biopsy diagnosis, the cancer diagnosis rate for the repeated biopsies was 19.8%, 22.6%, 40.0%, and 53.1%, for the patients with NEM, HGPIN, suspicious, and Susp-HGPIN, respectively. The repeated biopsy diagnosis rates did not vary dramatically when analyzed at 3-month intervals during the 1-year period. Also, a strong correlation (79%) was observed between the number of tissue samples obtained at the initial and repeated biopsy procedures. In a subset of patients with free and total prostate-specific antigen (PSA) results obtained before the repeated biopsy (n = 813), we were able to construct a multivariate logistic regression algorithm using the patients' age, initial biopsy diagnosis, total PSA, and free/total PSA ratio that could predict the likelihood of cancer on the repeated biopsy with an accuracy of 70%.
Conclusions: Men who have an initial noncancerous biopsy diagnosis remain at risk of prostate cancer, especially if the initial diagnosis was suspicious or Susp-HGPIN. These data suggest that the initial biopsy strategy needs to be improved and/or expanded to increase the overall cancer detection rate in the primary biopsy. In addition, combining factors such as the initial biopsy diagnosis, family history, digital rectal examination results, prostate gland volume, age, total PSA, and free/total PSA ratio could provide valuable information for predicting the likelihood of cancer.