Spatial distribution of prostate cancers undetected on initial needle biopsies

The spatial distribution of cancer foci of prostate carcinomas with negative initial biopsies was compared to that of prostate carcinomas with positive initial biopsies to detect areas in which carcinomas were more frequently located when the initial biopsy was negative.

Twenty patients with prostate cancer and a negative initial biopsy trial were detected among 218 patients with preceding systematic biopsies (9.2%) in our hospital. Analysis of the prostatectomy specimens regarding cancer distribution, multifocality, tumour size, Gleason score, and stage was performed using pathohistological techniques and three-dimensional computer reconstruction.

Prostatectomy specimens with negative initial biopsies showed more frequently cancer foci in apical (p<0.0001) and dorsal (p<0.02) prostatic compartments, higher incidence of multifocality (p<0.01), and smaller size of carcinoma foci (p<0.00003) compared to carcinomas in 81 stage-matched prostatectomy specimens with positive initial biopsies. Comparing both groups, no significant differences were noted in Gleason score of preoperative biopsies and prostatectomies, prostate weight, prostate-specific antigen (PSA) level, digital rectal examination, and patients age.

Missing the cancer in clinically significant prostate carcinomas by current systematic biopsy techniques may also be due to an apico-dorsal cancer location, particularly in combination with multifocality and small size of carcinoma foci in large prostates. In case of reasonable clinical suspicion of prostate cancer and negative initial biopsy, an early repeat biopsy with special emphasis on the apico-dorsal peripheral zone should be envisaged.