Transrectal Ultrasonography: Is It Ready for Routine Use?-Reply

In Reply.—  In the recent editorial on transrectal ultrasonography, the efficacy of ultrasonically guided radioactive seed implants was judged to be investigational because the use of surgically placed¹²⁵I seeds has not been as effective as external beam radiation in controlling this disease.¹ Nevertheless, Dr Baumgartner cites a recent study² in which the rate of positive prostate biopsy findings following interstitial radiation therapy was similar to the rate observed following external beam radiation therapy. Based on these data, he apparently concludes that interstitial radiation is as effective as external beam radiation.There are two problems with the study cited. First, there may have been a substantial selection bias, because 60% of the patients did not undergo a prostate biopsy following treatment. Second, although the number of cases in each group was small, the rates of positive prostate biopsy findings were higher for patients with moderate and poorly