title: Adverse effects of androgen deprivation therapy on persistent genitourinary complications after carbon ion radiotherapy for prostate cancer.
abstract: OBJECTIVE
  To determine the risk factors for persistent late genitourinary (GU) morbidity after carbon ion radiotherapy (C-ion RT) for prostate cancer.
  
  
  METHODS
  Between April 2000 and November 2003, a Phase II study of 175 prostate cancer patients was performed to assess C-ion RT with a dose fractionation (66 Gray equivalent in 20 fractions) established from previous Phase I-II studies. The effects of the clinical and dosimetric parameters on the occurrence of persistent GU toxicity in 172 patients who survived for >18 months after C-ion RT were examined retrospectively. C-ion RT alone was performed for 33 low-risk patients, and 139 high-risk patients received C-ion RT combined with androgen deprivation therapy (ADT).
  
  
  RESULTS
  Grade 1 and 2 persistent GU toxicities developed in 36 (21%) and 3 (2%) patients, respectively. The use of long-course ADT (>or=24 months) and acute GU toxicity were associated with the occurrence of persistent toxicity by multivariate analysis (p = 0.016 and p = 0.048, respectively), but short-course ADT (<24 months) had no effect on the development of toxicity (p = 0.35). The 5-year actuarial complication rate of 80 patients undergoing long-course ADT was 31.1%; the corresponding rate for the 92 patients who received no ADT or short-course ADT was 22.2%.
  
  
  CONCLUSIONS
  Adverse effects with long-course ADT on persistent GU morbidity were observed in this study. Additional investigation is needed to identify suitable ADT administration according to risk groups, but long-course ADT should not be adopted for non-high-risk prostate cancer patients to reduce the GU toxicity rate with C-ion RT.
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuji
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kamada
authors.forename: Naoki
authors.initials: N
authors.lastname: Hirasawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yanagi
authors.forename: Jun-Estu
authors.initials: JE
authors.lastname: Mizoe
authors.forename: Koichiro
authors.initials: K
authors.lastname: Akakura
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Jun
authors.initials: J
authors.lastname: Shimazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Tsujii
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000726:Androgen Antagonists / Q000009:adverse effects* / Q000627:therapeutic use; D002250:Carbon Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use*; D003131:Combined Modality Therapy / Q000379:methods; D019583:Dose Fractionation, Radiation; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009919:Orchiectomy; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery; D011832:Radiation Injuries / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014521:Urethra / Q000033:anatomy & histology / Q000528:radiation effects; D014555:Urination Disorders / Q000453:epidemiology* / Q000209:etiology; D014566:Urogenital System / Q000528:radiation effects
chemical_list: D000726:Androgen Antagonists; D002250:Carbon Radioisotopes