Urinary morbidity with a modified peripheral loading technique of transperineal I-125 prostate implantation

Purpose: Analysis of urinary morbidity within the first 12 months following a modified peripheral loading technique for permanent transperineal transr ectal ultrasound (TRUS) guided I-125 prostate implantation and comparison o f urinary morbidity with various clinical and implant parameters. Materials and Methods: Between October 1, 1996, and March 11, 1998, 87 pati ents with favorable, early stage prostate cancer were treated with permanen t transperineal TRUS guided I-125 prostate implantation. A peripheral loadi ng technique was utilized for source placement with 75-80% source distribut ion in the periphery and 20-25% source distribution centrally. A mean total activity of 38 mCi of I-125 was implanted (range, 19-66 mCi). The mean sou rce activity was 0.43 mCi/source (range, 0.26-0.61 mCi/source) and the mean number of sources implanted was 88 (range, 56-134). The minimum prescribed dose to the prostate was 145 Gy. The median D-90, V-100, and V-150 were 15 2 Gy (range, 104-211 Gy), 92% (range, 71-99%), and 61% (range, 11-89%), res pectively. The median follow-up time was 19 months (range, 12-29 months). U rinary morbidity was scored at 3 weeks and then at 3-month intervals for th e first 2 years using a modified Radiation Therapy Oncology Group (RTOG) gr ading system (scale 0-5). Results: Most patients developed at least minor urinary symptoms with frequ ency or nocturia being the most common. Overall, 79% (69/87) of patients ex perienced urinary morbidity with 21% (18/87) reporting no symptoms. The inc idence of overall Grade 1 urinary morbidity was 37% (32/87); Grade 2 morbid ity was 37% (32/87); and Grade 3 morbidity was 6% (5/87). There was no Grad e 4 or 5 morbidity. The incidence of Grade 0 frequency/nocturia was 36% (31 /87); Grade 1 was 33% (29/87); Grade 2 was 30% (26/87); and Grade 3 was 1% (1/87). Grade 0 dysuria was seen in 56% (49/87) of patients; 32% (28/87) ha d Grade 1; 10% (9/87) Grade 2; and 1% (1/87) Grade 3 dysuria. Most urinary symptoms started a few weeks after implantation and began to subside by 6 m onths. At 12 months, 22% (19/87) of patients had persistent urinary symptom s (78% Grade ii, 15% Grade 1, 3% Grade 2, and 3% Grade 3). The mean urethra l point dose was 174 Gy (range, 99-315 Gy). The mean number of sources impl anted correlated significantly with the likelihood of developing acute urin ary morbidity (p = 0.03). The total activity implanted also correlated with the morbidity outcome dysuria (p = 0.01) with a threshold seen at 37 mCi. Urethral point dose, source activity, intraoperative TRUS prostate volume, D-90, V-100, V-150, patient age, pretreatment PSA, Gleason score, and T sta ge did not correlate with morbidity. Conclusions: Permanent transperineal TRUS guided I-125 prostate implantatio n using a modified peripheral loading technique is associated with mild uri nary morbidity that resolves in 78% of patients by 12 months. Grade 3 urina ry morbidity was encountered in only 6% (5/87) of patients. Urinary morbidi ty may be related to the total number of sources implanted and/or the total activity implanted. Overall urinary morbidity was not correlated with uret hral point dose, source activity, intraoperative TRUS prostate volume, D-90 , V-100, V-150, patient age, pretreatment PSA, Gleason score, and T stage. The low incidence of urinary morbidity may be a consequence of our modified peripheral loading technique and/or the selection of patients with good-to -excellent preimplant urological parameters. Longer follow-up is necessary to assess biochemical control rates and long-term morbidity. (C) 2000 Elsev ier Science Inc.