Needle biopsy associated tumor tracking of adenocarcinoma of the prostate

We reviewed 350 previously biopsied completely submitted clinical stage B radical prostatectomy specimens resected between January 1, 1987 and December 31, 1988 in an attempt to identify the incidence of needle biopsy associated tumor tracking into periprostatic soft tissue. We identified 7 cases (2.0%) of needle biopsy associated tumor tracking, 3 in which the only tumor penetration in the gland was limited to the needle track. The maximal soft tissue extension from the biopsy site ranged from 0.1 to 1.2 cm. and approached the nearest soft tissue margin to within 0.5 mm. in 4 cases. In contrast to prior reports showing clinically evident tracking only with transperineal biopsies from high grade tumors, 6 of our 7 cases were of intermediate grade (in the glandular and tracking components) and 6 had transrectal biopsies. Needle biopsy associated tumor tracking occurred with core (14 gauge) and biopsy gun needles (18 gauge). An additional 13 cases (3.7%) showed some features of needle biopsy associated tumor tracking but they were equivocal. These findings have significant implications in light of recent proposals advocating serial mapping of prostate cancer using the biopsy gun with potential conservative observation of smaller tumors.