title: A comparison of the impact of isotope ((125)I vs. (103)Pd) on toxicity and biochemical outcome after interstitial brachytherapy and external beam radiation therapy for clinically localized prostate cancer.
abstract: OBJECTIVE
  To compare biochemical outcomes and morbidity associated with iodine-125 ((125)I) and palladium-103 ((103)Pd) brachytherapy as part of combined modality therapy for clinically localized prostate cancer.
  
  
  METHODS
  Between October 2002 and December 2008, 259 patients underwent prostate brachytherapy ((125)I prescription dose, 110Gy: n=199; (103)Pd prescription dose, 100Gy: n=60) followed by external beam radiotherapy (median dose, 50.4Gy). 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.
  
  
  RESULTS
  Overall, acute Grade ≥2 genitourinary toxicity occurred in 21% and 30% of patients treated with (125)I and (103)Pd, 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 (125)I and (103)Pd 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 ≥2 gastrointestinal toxicity occurred in 7% of (125)I patients and 6% of patients treated with (103)Pd. Of 129 potent patients at baseline, there was better erectile function in patients who received (103)Pd (p=0.02); however, the followup was shorter for these patients. The 5-year prostate-specific antigen relapse-free survival for (125)I and (103)Pd patients was 95.2% and 98.2% (p=0.73), respectively.
  
  
  CONCLUSIONS
  There were no differences in acute or long-term genitourinary or gastrointestinal toxicity between (125)I and (103)Pd in combined modality therapy for prostate cancer. There may be less erectile toxicity with the use of (103)Pd; however, additional followup of these patients is needed. There was no significant difference in 5-year prostate-specific antigen relapse-free survival between (103)Pd and (125)I.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. kollmeim@mskcc.org
authors.forename: Marisa A
authors.initials: MA
authors.lastname: Kollmeier
authors.forename: Xin
authors.initials: X
authors.lastname: Pei
authors.forename: Ece
authors.initials: E
authors.lastname: Algur
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
authors.forename: Brett W
authors.initials: BW
authors.lastname: Cox
authors.forename: Gil'ad N
authors.initials: GN
authors.lastname: Cohen
authors.forename: Marco
authors.initials: M
authors.lastname: Zaider
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000706:statistics & numerical data*; D003131:Combined Modality Therapy; D015897:Comorbidity; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D010165:Palladium / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology*; D011868:Radioisotopes / Q000627:therapeutic use; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D020266:Radiotherapy, Conformal / Q000706:statistics & numerical data*; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D010165:Palladium