Clinical Results of Iridium-192 High Dose Rate Brachytherapy with External Beam Radiotherapy

Abstract

Here, we report the clinical results of iridium-192 high dose rate brachytherapy at Kanazawa University Hospital. The study population consisted of 166 patients diagnosed with T1c-T3bN0M0 prostate cancer treated with high dose rate brachytherapy and external beam radiotherapy and followed up for 6 months or longer. Treatment consisted of external beam radiotherapy to the prostate at 44 Gy/22 fractions and high dose rate brachytherapy at 18 Gy/3 fractions. Median follow-up interval was 31.5 months (range 6.2-88.7). The overall 5-year biological recurrence-free survival rate was 93.0%. The 5-year biological recurrence-free survival rates for the patients in low-, intermediate- and high-risk groups according to the D'Amico risk classification criteria were 96.1%, 89.0% and 91.6%, respectively. When limited to the group that did not receive adjuvant hormonal therapy, the 5-year biological recurrence-free survival rates for the patients in low-, intermediate- and high-risk groups were 96.0%, 96.3% and 82.9%, respectively. Grade 3 or greater adverse effects were rare. Urethral stricture was observed in only 1.0% of the patients. Eighty percent of patients retained erectile function after high dose rate brachytherapy and reported satisfaction with sexual function. High dose rate brachytherapy is considered a good form of treatment for localized prostate cancer, although longer follow-up is necessary.