title: Intensity-modulated radiotherapy causes fewer side effects than three-dimensional conformal radiotherapy when used in combination with brachytherapy for the treatment of prostate cancer.
abstract: OBJECTIVE
  To measure the benefits of intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3D-CRT) when used in combination with brachytherapy for the treatment of prostate cancer.
  
  
  METHODS
  We conducted a retrospective review of all patients with localized prostate cancer who received external-beam radiotherapy (EBRT) in combination with brachytherapy with at least 1 year follow-up (n = 812). Combination therapy consisted of (103)Pd or (125)I implant, followed by a course of EBRT. From 1993 to March 2003 521 patients were treated with 3D-CRT, and from April 2003 to March 2009 291 patients were treated with IMRT. Urinary symptoms were prospectively measured with the International Prostate Symptom Score questionnaire with a single quality of life (QOL) question; rectal bleeding was assessed per the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer Late Radiation Morbidity Scoring Schema. The Pearson χ(2) test was used to compare toxicities experienced by patients who were treated with either IMRT or 3D-CRT. Logistic regression analyses were also performed to rule out possible confounding factors.
  
  
  RESULTS
  Within the first 3 months after treatment, patients treated with 3D-CRT scored their urinary symptoms as follows: 19% mild, 44% moderate, and 37% severe; patients treated with IMRT scored their urinary symptoms as follows: 36% mild, 47% moderate, and 17% severe (p < 0.001). The 3D-CRT patients rated their QOL as follows: 35% positive, 20% neutral, and 45% negative; IMRT patients rated their QOL as follows: 51% positive, 18% neutral, and 31% negative (p < 0.001). After 1 year of follow-up there was no longer any difference in urinary morbidity between the two groups. Logistic regression confirmed the differences in International Prostate Symptom Score and QOL in the acute setting (p < 0.001 for both). Grade ≥ 2 rectal bleeding was reported by 11% of 3D-CRT patients and 7% of IMRT patients (p = 0.046); logistic regression analysis also confirmed this observation (p = 0.040).
  
  
  CONCLUSIONS
  When used in combination with brachytherapy, IMRT offers less Grade ≥ 2 rectal bleeding, less acute urinary toxicities, and is associated with a higher QOL compared with 3D-CRT.
authors.affiliation: Department of Radiation Oncology, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Forsythe
authors.forename: Seth
authors.initials: S
authors.lastname: Blacksburg
authors.forename: Nelson
authors.initials: N
authors.lastname: Stone
authors.forename: Richard G
authors.initials: RG
authors.lastname: Stock
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy / Q000009:adverse effects / Q000379:methods; D005500:Follow-Up Studies; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010165:Palladium / Q000627:therapeutic use; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011788:Quality of Life; D011868:Radioisotopes / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods; D012002:Rectal Diseases / Q000175:diagnosis / Q000209:etiology*; D012044:Regression Analysis; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D014555:Urination Disorders / Q000145:classification / Q000209:etiology*
chemical_list: D007457:Iodine Radioisotopes; D011868:Radioisotopes; D010165:Palladium