TRANSPERINEAL ULTRASOUND-GUIDED RADIOACTIVE SEED IMPLANTATION FOR ORGAN-CONFINED CARCINOMA OF THE PROSTATE

Purpose: This retrospective study was undertaken to: (a) determine the prognostic significance of pretreatment and 1-year nadir serum prosta te specific antigen (PSA) levels in organ-confined carcinoma of the pr ostate treated with ultrasound-guided radioactive I-125 Seed implantat ion; (b) determine the factors associated with postimplant morbidity a nd whether modification of the technique would reduce morbidity; (c) e valuate the local control rate and disease-free survival of patients u ndergoing seed implantation. Methods and Materials: From October 1988 through December 1992, 142 patients with organ-confined adenocarcinoma of the prostate and a Gleason score less than or equal to 7 underwent ultrasound-guided radioactive I-125 seed implantation as an alternati ve to radical prostatectomy. Patients were considered to have persiste nt or progressive disease if there was evidence of local progression o n digital exam, or if there were two consecutive increases in the PSA level. Patients suspected of persistent or progressive disease underwe nt restaging to include CT scan of the pelvis, bone scan, and ultrasou nd-guided prostate biopsy. Patients with increasing PSA levels in whic h active disease could not be confirmed were considered biochemical fa ilures with occult systemic disease and were offered hormone ablation. Results: With 1-6-year follow-up, median 30 months, the relapse patte rns were prostate 4 (2.8%), bone 4 (2.8%), rising PSA 16 (11%). Pretre atment PSA level correlated with subsequent recurrence; pretreatment P SA less than or equal to 4 (0), 4.1 to 10 (14%), 10.1 to 20 (21%), 20. 1 to 50 (58%). Disease free survival at 2 years was 90% and at 5 years 76%. Nadir PSA (nPSA) at 1 year also correlated with recurrence: nPSA less than or equal to 1 (3%), nPSA 1 less than or equal to 4 (50%), a nd nPSA greater than or equal to 4 (100%). Seed implantation was well tolerated with 31% of patients experiencing RTOG morbidity greater tha n or equal to Grade 2, which typically consisted of transient radiatio n urethritis, which resolved with conservative measures. Eleven (8%) e xperienced RTOG morbidity greater than or equal to Grade 3. There was no correlation between number of seeds or total millicuries implanted and subsequent morbidity. However, reduction in the periurethral seed intensity reduced greater than or equal to Grade 3 morbidity from 11 t o 4%. Conclusion: Ultrasound-guided radioactive seed implantation prov ides excellent local control of 97%, with a median 30 month follow-up. Morbidity is comparable to other curative modalities and by modifying Blasko's technique to reduce radioactive seed strength in the periure thral area, significant morbidity is rare. Pretreatment PSA and the na dir PSA at 1 year are important predictors of subsequent disease outco me. With a liberal definition of systemic recurrence as two consecutiv e increases in PSA levels, the 5-year disease-free survival is 76%. (C ) 1997 Elsevier Science Inc.