Predictive Factors for Deterioration of Lower Urinary Tract Symptoms After Iodine-125 Brachytherapy in Prostate Cancer Patients

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Purpose : To identify predictive factors for deterioration of lower urinary tract symptoms (LUTS) after iodine-125 (¹²⁵I) brachytherapy for prostate cancer.
Materials and Methods : 42 patients with localized prostate cancer treated with ¹²⁵I brachytherapy as monotherapy between January 2013 and October 2014 were reviewed. In all patients, the prescribed dose was 160 Gy. Patients were asked to complete the International Prostate Symptom Score (IPSS) questionnaire just before and 3 months after the treatment. With an increase in IPSS ≥ 12 points defined as indicating obvious deterioration of LUTS (ODL), we analyzed the association between ODL and the following factors : age ; total activity of the sources ; prostate volume ; and dose-volume histogram (DVH) parameters, including V150 (%) of the prostate, V150 (cc) of the prostate, and D30 (Gy) of the urethra (minimal dose received by 30% of the urethral volume).
Results : Seventeen (40.5%) patients developed ODL. On univariate analyses, V150 (%) and V150 (cc) were found to be significantly associated with ODL. On multivariate analysis, only V150 (cc) was shown to have a significant relationship with ODL (P＝0.039).
Conclusion : V150 (cc) could be a predictive factor for deterioration of LUTS after ¹²⁵I brachytherapy in prostate cancer patients.