title: Clinical results of conformal versus intensity-modulated radiotherapy using a focal simultaneous boost for muscle-invasive bladder cancer in elderly or medically unfit patients.
abstract: BACKGROUND
  For elderly or medically unfit patients with muscle-invasive bladder cancer, cystectomy or chemotherapy are contraindicated. This leaves radical radiotherapy as the only treatment option. It was the aim of this study to retrospectively analyze the treatment outcome and associated toxicity of conformal versus intensity-modulated radiotherapy (IMRT) using a focal simultaneous tumor boost for muscle-invasive bladder cancer in patients not suitable for cystectomy.
  
  
  METHODS
  One hundred eighteen patients with T2-4 N0-1 M0 bladder cancer were analyzed retrospectively. Median age was 80 years. Treatment consisted of either a conformal box technique or IMRT and included a simultaneous boost to the tumor. To enable an accurate boost delivery, fiducial markers were placed around the tumor. Patients were treated with 40 Gy in 20 fractions to the elective treatment volumes, and a daily tumor boost up to 55-60 Gy.
  
  
  RESULTS
  Clinical complete response was seen in 87 % of patients. Three-year overall survival was 44 %, with a locoregional control rate of 73 % at 3 years. Toxicity was low, with late urinary and intestinal toxicity rates grade ≥ 2 of 14 and 5 %, respectively. The use of IMRT reduced late intestinal toxicity, whereas fiducial markers reduced acute urinary toxicity.
  
  
  CONCLUSIONS
  Radical radiotherapy using a focal boost is feasible and effective for elderly or unfit patients, with a 3-year locoregional control of 73 %. Toxicity rates were low, and were reduced by the use of IMRT and fiducial markers.
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. l.j.lutkenhaus@amc.uva.nl.
authors.forename: Lotte J
authors.identifier: http://orcid.org/0000-0002-1348-9349
authors.initials: LJ
authors.lastname: Lutkenhaus
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Rob M
authors.initials: RM
authors.lastname: van Os
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Arjan
authors.initials: A
authors.lastname: Bel
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Maarten C C M
authors.initials: MC
authors.lastname: Hulshof
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015653:Cystectomy / Q000379:methods; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011878:Radiotherapy / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D001749:Urinary Bladder Neoplasms / Q000532:radiotherapy*
keywords: Bladder cancer; Focal boost; Intensity-modulated radiotherapy; Radical radiotherapy; Toxicity