title: Prospective phase II study of image-guided local boost using a real-time tumor-tracking radiotherapy (RTRT) system for locally advanced bladder cancer.
abstract: OBJECTIVE
  The real-time tumor-tracking radiotherapy system with fiducial markers has the advantage that it can be used to verify the localization of the markers during radiation delivery in real-time. We conducted a prospective Phase II study of image-guided local-boost radiotherapy for locally advanced bladder cancer using a real-time tumor-tracking radiotherapy system for positioning, and here we report the results regarding the safety and efficacy of the technique.
  
  
  METHODS
  Twenty patients with a T2-T4N0M0 urothelial carcinoma of the bladder who were clinically inoperable or refused surgery were enrolled. Transurethral tumor resection and 40 Gy irradiation to the whole bladder was followed by the transurethral endoscopic implantation of gold markers in the bladder wall around the primary tumor. A boost of 25 Gy in 10 fractions was made to the primary tumor while maintaining the displacement from the planned position at less than ±2 mm during radiation delivery using a real-time tumor-tracking radiotherapy system. The toxicity, local control and survival were evaluated.
  
  
  RESULTS
  Among the 20 patients, 14 were treated with concurrent chemoradiotherapy. The median follow-up period was 55.5 months. Urethral and bowel late toxicity (Grade 3) were each observed in one patient. The local-control rate, overall survival and cause-specific survival with the native bladder after 5 years were 64, 61 and 65%.
  
  
  CONCLUSIONS
  Image-guided local-boost radiotherapy using a real-time tumor-tracking radiotherapy system can be safely accomplished, and the clinical outcome is encouraging. A larger prospective multi-institutional study is warranted for more precise evaluations of the technological efficacy and patients' quality of life.
authors.affiliation: *Department of Radiation Medicine, Hokkaido University Graduate School of Medicine/School of Medicine, Sapporo, Japan. sshing@med.hokudai.ac.jp.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nishioka
authors.forename: Shinichi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Nobuo
authors.initials: N
authors.lastname: Shinohara
authors.forename: Yoichi M
authors.initials: YM
authors.lastname: Ito
authors.forename: Takashige
authors.initials: T
authors.lastname: Abe
authors.forename: Satoru
authors.initials: S
authors.lastname: Maruyama
authors.forename: Rumiko
authors.initials: R
authors.lastname: Kinoshita
authors.forename: Keiichi
authors.initials: K
authors.lastname: Harada
authors.forename: Noboru
authors.initials: N
authors.lastname: Nishikawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Miyamoto
authors.forename: Rikiya
authors.initials: R
authors.lastname: Onimaru
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D059248:Chemoradiotherapy; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D007422:Intestines / Q000528:radiation effects; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D011446:Prospective Studies; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome; D014521:Urethra / Q000528:radiation effects; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*
chemical_list: D000970:Antineoplastic Agents; D009944:Organoplatinum Compounds; C053989:nedaplatin
keywords: bladder cancer; combined modality therapy; image-guided radiation therapy