title: After low and high dose-rate interstitial brachytherapy followed by IMRT radiotherapy for intermediate and high risk prostate cancer.
abstract: BACKGROUND
  The study aimed to compare urinary symptoms in patients with clinically localized prostate cancer after a combination of either low-dose-rate or high-dose-rate interstitial brachytherapy along with intensity-modulated radiation therapy (LDR-ISBT + IMRT or HDR-ISBT + IMRT).
  
  
  METHODS
  From June 2009 to April 2014, 16 and 22 patients were treated with LDR-ISBT + IMRT and HDR-ISBT + IMRT, respectively. No patient from these groups was excluded from this study. The prescribed dose of LDR-ISBT, HDR-ISBT, and IMRT was 115 Gy, 20 Gy in 2 fractions, and 46 Gy in 23 fractions, respectively. Obstructive and irritative urinary symptoms were assessed by the International Prostate Symptom Score (IPSS) examined before and after treatments. After ISBT, IPSS was evaluated in the 1st and 4th weeks, then every 2-3 months for the 1st year, and every 6 months thereafter.
  
  
  RESULTS
  The median follow-up of the patients treated with LDR-ISBT + IMRT and HDR-ISBT + IMRT was 1070.5 days and 1048.5 days, respectively (p = 0.321). The IPSS-increment in the LDR-ISBT + IMRT group was greater than that in the HDR-ISBT + IMRT between 91 and 180 days after ISBT (p = 0.015). In the LDR-ISBT + IMRT group, the IPSS took longer time to return to the initial level than in the HDR-ISBT + IMRT group (in LDR-ISBT + IMRT group, the recovery time was 90 days later). The dose to urethra showed a statistically significant association with the IPSS-increment in the irritative urinary symptoms (p = 0.011). Clinical outcomes were comparable between both the groups.
  
  
  CONCLUSIONS
  Both therapeutic modalities are safe and well suited for patients with clinically localized prostate cancer; however, it took patients longer to recover from LDR-ISBT + IMRT than from HDR-ISBT + IMRT. It is possible that fast dose delivery induced early symptoms and early recovery, while gradual dose delivery induced late symptoms and late recovery. Urethral dose reductions were associated with small increments in IPSS.
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan. satonaka@ncc.go.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Murakami
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Inaba
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Wakita
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okamoto
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Rei
authors.initials: R
authors.lastname: Umezawa
authors.affiliation: Department of Radiation Oncology, Showa University Koto Toyosu Hospital, 5-1-38 Toyosu, Koto-ku, Tokyo, 135-8577, Japan.
authors.forename: Madoka
authors.initials: M
authors.lastname: Morota
authors.affiliation: Department of Radiation Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-0063, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Sumi
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Igaki
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tsukiji 5-1-1, Tokyo, 104-0045, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Itami
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000150:complications / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology / Q000473:pathology; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D014521:Urethra / Q000473:pathology* / Q000528:radiation effects
keywords: Clinically localized prostate cancer; High-dose-rate brachytherapy; Intensity-modulated radiation therapy (IMRT); International Prostate Symptom Score (IPSS); Low-dose-rate brachytherapy