Yield of cancer tissue from prostatic needle biopsy.

This study concerns the quality of human prostatic cancer needle biopsy specimens for routine diagnosis and for bioassay. We examined routine hematoxylin and eosin-stained microscopic sections from 20 prostatic cancer patients, 159 needle cores in all, 71 positive for tumor. Linear core measurements were made with a calibrated ocular micrometer, each segment counted positive if it contained any tumor. Among all subjects there were 35.5 cm of tumor-bearing core length, 26 per cent of the total core length but 60 per cent of the length if completely negative cores were excluded. From these data we calculate a 91 per cent probability of detecting any cancer present if at least 4 cores are taken.