Between October 2002 and December 2008, 259 patients underwent prostate brachytherapy (125I prescription dose, 110 Gy: n = 199; 103Pd prescription dose, 100 Gy: n = 60) followed by external beam radiotherapy (median dose, 50.4 Gy). Eighty-seven patients also received neoadjuvant androgen deprivation therapy. Toxicities were recorded with CTCAE v 3.0, International Prostate Symptoms Score (IPSS), and International Index of Erectile Function questionnaires.
Overall, acute Grade 鈮? genitourinary toxicity occurred in 21%and 30%of patients treated with 125I and 103Pd, respectively (p = 0.16). There were no significant differences in IPSS change or urinary quality-of-life scores between the isotopes at 4, 6, or 12 months (p = 0.20, 0.21, and 1.0, respectively). IPSS resolution occurred at a median of 11 and 6 months for 125I and 103Pd patients, respectively (p = 0.03). On multivariate analysis, only the use of neoadjuvant androgen deprivation therapy was predictive of time to IPSS resolution (p = 0.046). Late Grade 鈮? gastrointestinal toxicity occurred in 7%of 125I patients and 6%of patients treated with 103Pd. Of 129 potent patients at baseline, there was better erectile function in patients who received 103Pd (p = 0.02); however, the followup was shorter for these patients. The 5-year prostate-specific antigen relapse-free survival for 125I and 103Pd patients was 95.2%and 98.2%(p = 0.73), respectively.
There were no differences in acute or long-term genitourinary or gastrointestinal toxicity between 125I and 103Pd in combined modality therapy for prostate cancer. There may be less erectile toxicity with the use of 103Pd; however, additional followup of these patients is needed. There was no significant difference in 5-year prostate-specific antigen relapse-free survival between 103Pd and 125I.