title: A comparison of clinical outcomes between three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for prostate cancer.
abstract: BACKGROUND
  Intensity-modulated radiation therapy (IMRT) reduces the dose delivered to organs at risk. However, there have been few direct comparisons of IMRT with conventional three-dimensional conformal radiotherapy (3DCRT). The aim of this study was to evaluate the clinical benefit of IMRT in terms of toxicity and biochemical control.
  
  
  METHODS
  The medical records of 203 consecutive patients with localized to non-metastatic (stage T1a-T3bN0M0) prostate cancer between 2007 and 2011 were retrospectively reviewed. The prescribed dose was 76 Gy delivered in 38 fractions in both the 3DCRT and IMRT treatment groups. The frequency of grade 2 or greater late gastrointestinal (GI) and genitourinary toxicity and biochemical control were estimated by the log-rank test and Cox proportional hazards model with and without adjustment by the propensity score for treatment choice.
  
  
  RESULTS
  A total of 159 patients were included in the study (3DCRT: 70 patients, IMRT: 89 patients). The median follow-up period was 4.7 years. The estimated 5-year cumulative risk of late GI toxicity was significantly lower in the IMRT group than in the 3DCRT group (3.6 vs 13.2%, respectively, p = 0.022). After adjustment by propensity score, IMRT remained associated with a lower risk of late GI toxicity (hazard ratio 0.22; 95% confidence interval 0.058-0.85; p = 0.028). The 5-year biochemical failure-free rate was 93.2% in the 3DCRT group and 95.4% in the IMRT group (non-significant difference).
  
  
  CONCLUSIONS
  The incidence of late GI toxicity was significantly lower in the IMRT group than in the 3DCRT group, while the biochemical control rates were no different between the two groups. These clinical data suggest the benefit of IMRT in the reduction of late GI toxicity.
authors: Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Hon-Komagome, Bunkyo Ward, Tokyo, 113-8677, Japan. shimizuguchi@cick.jp.
authors: Takuya
authors: http://orcid.org/0000-0001-9763-0743
authors: T
authors: Shimizuguchi
authors: Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Hon-Komagome, Bunkyo Ward, Tokyo, 113-8677, Japan.
authors: Keiji
authors: K
authors: Nihei
authors: Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Hon-Komagome, Bunkyo Ward, Tokyo, 113-8677, Japan.
authors: Tomoyuki
authors: T
authors: Okano
authors: Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Hon-Komagome, Bunkyo Ward, Tokyo, 113-8677, Japan.
authors: Yumiko
authors: Y
authors: Machitori
authors: Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Hon-Komagome, Bunkyo Ward, Tokyo, 113-8677, Japan.
authors: Kei
authors: K
authors: Ito
authors: Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Hon-Komagome, Bunkyo Ward, Tokyo, 113-8677, Japan.
authors: Katsuyuki
authors: K
authors: Karasawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: 3DCRT; IMRT; Late toxicity; Prostate