title: Intensity-modulated radiotherapy reduces toxicity with similar biochemical control compared with 3-dimensional conformal radiotherapy for prostate cancer: A randomized clinical trial.
abstract: BACKGROUND
  The objective of this article was to report the results from a randomized clinical trial comparing intensity-modulated radiotherapy (IMRT) with 3-dimensonal conformal radiotherapy (3DCRT) for the treatment of prostate cancer on a hypofractionated schedule.
  
  
  METHODS
  The authors randomly assigned 215 men who had localized prostate cancer to receive hypofractionated radiotherapy to a total dose of 70 grays (Gy) in 25 fractions (at 2.8 Gy per fraction) using either IMRT or 3DCRT. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity were prospectively evaluated according to modified Radiation Therapy Oncology Group criteria. Biochemical control was defined according to the Phoenix criteria (prostate-specific antigen nadir + 2 ng/mL).
  
  
  RESULTS
  In total, 215 patients were enrolled in the IMRT group (n = 109) or the 3DCRT group (n = 106). The 3DCRT arm had a 27% rate of grade ≥ 2 acute GU toxicity compared with a 9% rate in the IMRT arm (P = .001) and a 24% rate of grade ≥ 2 acute GI toxicity compared with a 7% rate in the IMRT arm (P = .001). The maximal rate of grade ≥2 late GU toxicity during the entire period of follow-up was 3.7% in the IMRT group versus 12.3% in the 3DCRT group (P = .02). The maximal rate of grade ≥2 late GI toxicity during the entire follow-up was 6.4% in the IMRT group versus 21.7% in the 3DCRT group (P = .001). The 5-year rate of freedom from biochemical failure was 95.4% in the IMRT arm and 94.3% in the 3DCRT arm (P = .678).
  
  
  CONCLUSIONS
  IMRT reduced the delivery of significant radiation doses to the bladder and rectum using a similar target volume. This dosimetric advantage resulted in a lower rate of acute/late grade ≥ 2 GI and GU toxicity for IMRT compared with 3DCRT. Cancer 2016;122:2004-11. © 2016 American Cancer Society.
authors.affiliation: Department of Radiation Oncology, Marilia Medical School, Marília, Sao Paulo, Brazil.
authors.forename: Gustavo Arruda
authors.initials: GA
authors.lastname: Viani
authors.affiliation: Department of Radiation Oncology, Marilia Medical School, Marília, Sao Paulo, Brazil.
authors.forename: Bruno Silveira
authors.initials: BS
authors.lastname: Viana
authors.affiliation: Department of Radiation Oncology, Marilia Medical School, Marília, Sao Paulo, Brazil.
authors.forename: Jose Eduardo Chicareli
authors.initials: JE
authors.lastname: Martin
authors.affiliation: Department of Radiation Oncology, Marilia Medical School, Marília, Sao Paulo, Brazil.
authors.forename: Bruno Tiago
authors.initials: BT
authors.lastname: Rossi
authors.affiliation: Department of Radiation Oncology, Marilia Medical School, Marília, Sao Paulo, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Zuliani
authors.affiliation: Department of Radiation Oncology, Marilia Medical School, Marília, Sao Paulo, Brazil.
authors.forename: Eduardo Jose
authors.initials: EJ
authors.lastname: Stefano
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D000069473:Radiation Dose Hypofractionation; D011832:Radiation Injuries / Q000453:epidemiology*; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods; D016896:Treatment Outcome
chemical_list: D017430:Prostate-Specific Antigen
keywords: acute toxicity; conformal radiotherapy; intensity-modulated radiotherapy (IMRT); late toxicity; prostate cancer