The significance of post-irradiation prostate biopsy with long-term follow-up.
Ninety-four patients, Stage A2-C, definitively irradiated for adenocarcinoma of the prostate from 1975 to 1981 underwent digitally directed transperineal needle biopsy of a clinically negative prostate gland at least 18 months post-therapy. Ten of 55 patients (18%) treated with Iodine-125 implantation and 7 of 39 patients (18%) externally irradiated were found to have positive biopsy specimens. Overall, clinical local failure occurred in 53% of patients with positive biopsy results but in only 18% with negative specimens, p = .006. The false negative biopsy rate in patients treated with I-125 was nearly three times that for external beam, 24% versus 9%, perhaps because of the greater possibility of inhomogeneous dose distribution with I-125, allowing for a higher degree of sampling error. Actuarial local failure at 5 years was 44% versus 8% with positive and negative biopsies, respectively, and 75% versus 24% at 10 years (p = .0001). The distant metastatic rate was twice as high in biopsy-positive as compared to biopsy-negative patients, 71% versus 35%, p = .015. Actuarially, only 19% of patients with a positive biopsy are NED at 10 years as compared to 62% of those with a negative biopsy (p = .0001). PSA values are supportive in those patients thought to be disease-free. The incidence of positive biopsy and associated local recurrence are in keeping with clinical treatment failure rates as reported in multiple studies to date.
Kuban
D A
DA
Department of Radiation Oncology, Eastern Virginia Medical School, Norfolk, VA 23507.
el-Mahdi
A M
AM
Schellhammer
P
P
D000230:Adenocarcinoma / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D001707:Biopsy, Needle; D001918:Brachytherapy; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D012189:Retrospective Studies; D015996:Survival Rate
D007457:Iodine Radioisotopes