title: Predictive factors for urinary toxicity after iodine-125 prostate brachytherapy with or without supplemental external beam radiotherapy.
abstract: We examined the factors associated with urinary toxicities because of brachytherapy with iodine-125 with or without supplemental external beam radiotherapy (EBRT) for prostate cancer.
  
  
  
  We investigated 1313 patients with localized prostate cancer treated with iodine-125 brachytherapy with or without supplemental EBRT between 2003 and 2009. The International Prostate Symptom Score (IPSS) and Common Terminology Criteria for Adverse Events data were prospectively determined. Patients, treatment, and implant factors were investigated for their association with urinary toxicity or symptoms.
  
  
  
  IPSS resolution was not associated with biologically effective dose (BED). Baseline IPSS, total needles, and the minimal dose received by 30% of the urethra had the greatest effect according to multivariate analysis (MVA). Urinary symptom flare was associated with baseline IPSS, age, BED, and EBRT on MVA. Urinary symptom flare and urinary Grade 2 or higher (G2+) toxicity occurred in 51%, 58%, and 67% (p = 0.025) and 16%, 22%, and 20% (p = 0.497) of the <180, 180-220, and >220 Gy BED groups, respectively. Urinary G2+ toxicity was associated with baseline IPSS, neoadjuvant androgen deprivation therapy (NADT), and seed density on MVA. When we divided patients into four groups according to prostate volume (<30 cc or ≥30 cc) and NADT use, urinary G2+ toxicity was most commonly observed in those patients with larger prostates who received NADT, and least in the patients with smaller prostates and no NADT.
  
  
  
  NADT was associated with urinary G2+ toxicity. Higher dose and supplemental EBRT did not appear to increase moderate to severe urinary toxicities or time to IPSS resolution; however, it influenced urinary symptom flare.
authors.affiliation: Department of Radiology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan; Department of Radiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan. Electronic address: eriguchi@rad.med.keio.ac.jp.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Eriguchi
authors.affiliation: Department of Radiology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan.
authors.forename: Atsunori
authors.initials: A
authors.lastname: Yorozu
authors.affiliation: Department of Radiology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Kuroiwa
authors.affiliation: Department of Urology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan.
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Yagi
authors.affiliation: Department of Urology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nishiyama
authors.affiliation: Department of Urology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Saito
authors.affiliation: Department of Urology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan; Department of Radiology, International University of Health and Welfare Mita Hospital, Minato-ku, Tokyo, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Toya
authors.affiliation: Department of Radiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hanada
authors.affiliation: Department of Radiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Shiraishi
authors.affiliation: Department of Radiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Ohashi
authors.affiliation: Department of Radiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Shigematsu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000009:adverse effects; D001918:Brachytherapy / Q000009:adverse effects*; D006801:Humans; D007455:Iodine; D007457:Iodine Radioisotopes / Q000009:adverse effects; D059411:Lower Urinary Tract Symptoms / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000009:adverse effects; D009929:Organ Size; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000150:complications / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012307:Risk Factors; D012720:Severity of Illness Index; D000067251:Symptom Flare Up; D014521:Urethra / Q000528:radiation effects*
chemical_list: D000726:Androgen Antagonists; D007457:Iodine Radioisotopes; D007455:Iodine; D017430:Prostate-Specific Antigen
keywords: (125)I; Brachytherapy; Higher biological effective dose; Neoadjuvant androgen deprivation therapy; Prostate cancer; Supplemental external beam radiotherapy; Urinary toxicity