Histological characteristics of prostatic biopsies after 125iodine implantation.

There were 39 prostatic needle biopsies obtained from 33 patients with carcinoma of the prostate 1 to 3 years after definitive treatment with interstitial implantation using 125iodine radioactive sources. Of these biopsies 57 per cent obtained at 12 to 18 months and 73 per cent obtained at 19 to 36 months after implantation were negative for malignancy. All biopsies revealed histologic evidence of significant radiation injury. Neither the presence or absence of malignancy on biopsy nor the degree of radiation injury could be related to the initial stage and grade of the prostatic neoplasm.