Initial experience of focal therapy for prostate cancer using I-125 seed implantation: Unilateral ablation for patients selected by extended biopsy and MRI findings.

Abstract

99 Background: Focal therapy for prostate cancer could be a minimally invasive therapeutic option with the preservation of genitourinary function to reduce treatment associated complication under the appropriate selection of patients. We have reported the good predict ability to unilateral prostate cancer by extended prostate biopsy combined with transperineal and transrectal approaches (Eur Urol supple, 2009). Among the candidate ablative, brachytherapy which has been proved as a definitive therapy and applied worldwide has been thought to have potential for focal ablation due to its ability of dose and location adjustment by seed implantation under real-time monitoring. Based on the findings, focal therapy with hemiablation using I-125 seed implantation has been started in our instituion. The aim of study is to describe the initial experience of focal therapy for patients selected by extended biopsy and MRI findings. Methods: The eligible criteria for focal therapy to prostate cancer are as follows. Clinical stage is T2a or less. The positive cores of cancer are proven within unilateral lobe by extended prostate biopsy. There was no cancerous lesion in contralateral lobe by MRI. Gleason score in positive cores was 3 + 4 or less. Maximum cancer length was less than 5 mm. PSA value is less than 10 ng/mL. On the treatment, I-125 seeds were implanted to ablate the unilateral lobe with 160 Gy of the prescription dose. The protocol has been approved by the institutional ethics commit. Results: At present, 3 patients were enrolled in this study and underwent focal therapy with written informed consents. In all three cases, I-125 seeds implanted (number od seeds: 43, 39, and 37) to unilateral lobe without severe acute complication such as acute urinary retention. In one case that has been followed over 3months among the initial three cases, PSA values decreased to 2.07 mg/ml at 3 months after the seed implantation. Conclusions: To our knowledge, this is the first report about focal therapy by brachytherapy with hemiablative technique. In our initail experience, severe treatment associated complication has not been observed. No significant financial relationships to disclose.