Differences in tumor core distribution between palpable and nonpalpable prostate tumors in patients diagnosed using extensive transperineal ultrasound-guided template prostate biopsy.

BACKGROUND: The authors performed extensive transperineal ultrasound-guided template prostate biopsies to investigate carcinoma core distribution.
METHODS: Between August 2000 and May 2004, 371 men underwent template biopsies. Three hundred twelve patients had not undergone a previous biopsy (first group) and 59 had undergone previous transrectal sextant biopsies (repeat group). Of the 312 patients in the first group, 236 had normal digital rectal examination (DRE) findings (DRE- first group) and 76 patients had an abnormal DRE (DRE+ first group). A mean of 20.1 biopsy cores (range, 9-38 cores) was taken from the entire prostate. The region > 2.0 cm from the rectal face of the prostate was defined as the anterior region and the remaining area was defined as the posterior region.
RESULTS: In the DRE- first group, the carcinoma core rate (number of tumor cores/number of biopsy cores) in the anterior region (7.2%) did not differ from that of the posterior region (7.3%) (P = 0.9635). However, in the DRE+ first group, the carcinoma core rate in the posterior region (22.0%) was found to be higher than in the anterior region (13.2%) (P < 0.0001). In the repeat group, the carcinoma core rate in the posterior region (3.1%) was significantly (P = 0.0008) lower than that exhibited in the anterior region (7.2%).
CONCLUSIONS: The results of the current study suggest that nonpalpable prostate carcinoma is distributed equally within the entire prostate, although palpable carcinoma is distributed mainly in the posterior region and many of the tumor foci in the anterior region may be missed by a transrectal sextant biopsy. The examination of radical prostatectomy specimens is required to prove these results. (c) 2005 American Cancer Society.