Diagnosis of "suspicious for malignancy" in prostate biopsies: predictive value for cancer.

OBJECTIVES: Prostate needle biopsies occasionally contain an atypical small acinar proliferation (ASAP) that is suspicious for but not diagnostic of malignancy. The predictive value of ASAP for cancer has not been studied in a large series. METHODS: To determine the reproducibility and clinical significance of ASAP in a large urologic reference laboratory, we retrospectively studied 295 patients with ASAP diagnosed from 1991 to 1995. Each patient had at least one follow-up biopsy. Mean patient age was 68.0 years (range 40 to 89). Numerous clinical and histologic features were assessed to determine their predictive value for malignancy on subsequent biopsy. RESULTS: Adenocarcinoma was identified on follow-up biopsy in 125 patients (42%), with a median follow-up of 5.7 months (range 0.1 to 43). Gleason score varied from 4 to 9 (mean 6.2). Cumulative detection of 125 cancers was 90% after second biopsy and 99% after third biopsy. Serum prostate-specific antigen, digital rectal examination result, and patient age were not predictive of cancer on follow-up biopsy. Likewise, the number of biopsy cores and histologic findings including number of acini per focus of ASAP, number of foci of ASAP, degree of nuclear and nucleolar enlargement, and presence of luminal pink granular secretions, mucin, or crystalloids were not predictive of cancer. Stratifying our level of suspicion into three categories (favor benign, uncertain, and favor carcinoma) did not differentially predict subsequent cancer (44%, 44%, and 41% of patients, respectively; P = 0.86) nor the percentage of tissue involved by cancer. No clinical or pathologic feature affected the likelihood of subsequent cancer. In 39% of patients, cancer was only contralateral to or in a different sextant site from the initial ASAP site. CONCLUSIONS: The high predictive value of ASAP for subsequent adenocarcinoma warrants repeat biopsy. Sampling should include multiple sites in the prostate.

Positive prostate biopsy rate consistently increases with age at the same prostate-specific antigen level in patients with normal digital rectal examination.

OBJECTIVES: To examine the relationship between positive prostate biopsy rates and age over the range of serum prostate-specific antigen (PSA) concentrations of 4 to 10 ng/mL. METHODS: The rates for adenocarcinoma were calculated for prostate biopsy specimens received at UroCor Inc., Oklahoma City, Oklahoma between April 1995 and June 1997. The selection criteria were as follows: men between 50 and 79 years of age, normal digital rectal examination (DRE), prebiopsy PSA level between 4.01 and 10.0 ng/mL obtained within a 4-month period prior to receipt of biopsy, and no previous prostate biopsy. Five thousand six cases were selected out of 81,545 prostate biopsy specimens submitted by office-based urologists. The rates of positive prostate biopsies were stratified by age in decade increments and by PSA in increments of 1 ng/mL. The P values were calculated by the chi-square test. RESULTS: The patient mean age was 65.8 years. An overall increase in the positive prostate biopsy rate for men between 50 and 79 years of age as serum PSA increases from 4.01 to 10.0 ng/mL (P = 0.047) was found; however, this increase was less significant than the increase found in positive biopsy rates caused by age alone (P <0.0001). CONCLUSIONS: Undetected prostate cancer appears to be a major cause of the increasing serum PSA seen with advancing age.

Observations on pathology trends in 62,537 prostate biopsies obtained from urology private practices in the United States.

OBJECTIVES: To evaluate pathology trends of 62,537 first-time prostate needle-core biopsies submitted by office-based urologists, processed at a single pathology laboratory. METHODS: Prostate biopsy cases obtained over a 2-year period were assessed. Patient information included age, digital rectal examination (DRE) status, and prostate-specific antigen (PSA) serum levels. Biopsy pathology results included the number of tissue samples per case, Gleason score, presence of Gleason grades 4 or 5, percent of biopsy length with evidence of cancer, number of samples with cancer per biopsy, and determination of DNA ploidy status using microspectrophotometry. RESULTS: Adenocarcinoma, suspicious lesions, and isolated high-grade prostatic intraepithelial neoplasia (PIN) were diagnosed in 38.3%, 2.9%, and 4.1% of the biopsies, respectively. For each serum PSA and age range assessed, the positive biopsy rate and incidence of critical pathologic features increased consistently. The average percentage of biopsy length with evidence of tumor, the percentage of cases with Gleason grades 4 or 5, and the percentage of cases with an abnormal DNA ploidy all decreased significantly over the 2-year period (P <0.01). CONCLUSIONS: The number of tissue cores and anatomic sites (locations) being sampled per biopsy are increasing. The tumor size detected and percentage of cases with Gleason grades 4 and 5 are decreasing. There has been a slight increase in the number of biopsies performed on men younger than 60 years of age and a slight decrease in biopsies performed on men older than 70 years of age. The decline in meaningful pathologic features observed in biopsies over time may be clinically relevant to improved disease management.