To compare morbidity between two currently used iodine-125 seed implantation techniques for the treatment of localized prostate cancer.

Iodine-125 brachytherapy was used in 300 consecutive men with localized prostate cancer. Two seed implant techniques were used: preplanning, using preloaded needles, and intraoperative planning, using a Mick applicator. A comparison was made between the groups for urinary morbidity. The International Prostate Symptom Score was assessed prospectively among all patients. Computed tomography-based implant quality parameters were correlated with lower urinary system morbidity.

The median follow-up was 30 months. In both treatment groups, the International Prostate Symptom Score increased significantly for about 9 to 12 months and returned to baseline thereafter. The International Prostate Symptom Scores reached a higher level and remained at a higher level for a longer period in the intraoperative group. Although the differences were statistically significant, they were of mild clinical importance. Overall, the incidence of acute retention and the need for surgery was very low in both groups (2% and 1%, respectively). No differences were noted between the two groups. Significantly better computed tomography-based implant dosimetry parameters were noted with the intraoperative method. A positive correlation (P < 0.001) was found between the dosimetry parameters and symptom severity.

This prospective study reports the first large-scale comparison of urologic outcomes after two different seed implant techniques. Both were associated with very low urinary retention rates or other grade 3 or greater urologic morbidity. Almost all men had worse urinary symptoms for the first 6 to 9 months, regardless of the seed implant technique used. Patients treated with the intraoperative method demonstrated toxicity for a longer duration. Because of the much better gland isodose coverage and greater doses delivered in the intraoperative seed implantation, we favor this method.