NEEDLE BIOPSIES OF THE PROSTATE - WHAT CONSTITUTES ADEQUATE HISTOLOGIC SAMPLING

Objective.-The automated biopsy gun and increased screening for adenoc arcinoma of the prostate have led to increased numbers of biopsies wit h only tiny foci of prostatic carcinoma. Consequently, the risk of fai ling to sample a smalt focus of carcinoma histologically has increased as well. Most pathologists routinely sample prostatic needle biopsies at more than 1 level. An expert panel has recently suggested that pro static needle biopsies be sampled at at least 2 levels. However, there have been no studies measuring the amount of additional tissue sample d by multiple levels versus 1 level. Methods.-Forty-two prostatic need le biopsies were serially sectioned at 4-mu m levels. Hematoxylin-eosi n-stained slides were prepared from every fifth section. The total len gth of each biopsy was compared with the length sampled by 1 level (50 % through the block) and 3 levels (25%, 50%, and 75% through the block ). Results.-Sampling the tissue at 1 level missed an average of 23.4% of the total biopsy length. Sampling the tissue at 3 levels significan tly improved this average to 7% (P = .0001). Conclusions.-This study s hows that a single histologic section of a prostatic needle biopsy oft en fails to sample a significant portion of available tissue. This cou ld occasionally result in failure to sample a small focus of prostatic carcinoma. The authors recommend that prostatic needle biopsies be ro utinely sampled at 3 levels (approximately 25%, 50%, and 75% through t he block).