title: Simultaneous integrated boost irradiation after breast-conserving surgery: physician-rated toxicity and cosmetic outcome at 30 months' follow-up.
abstract: OBJECTIVE
  To evaluate toxicity and cosmetic outcome (CO) in breast cancer survivors treated with three-dimensional conformal radiotherapy with a hypofractionated, simultaneous integrated boost (3D-CRT-SIB) and to identify risk factors for toxicity, with special focus on the impact of age.
  
  
  METHODS
  Included were 940 consecutive disease-free patients treated for breast cancer (Stage 0-III) with 3D-CRT-SIB, after breast-conserving surgery, from 2005 to 2010. Physician-rated toxicity (Common Terminology Criteria for Adverse Events version 3.0) and CO were prospectively assessed during yearly follow-up, up to 5 years after radiotherapy. Multivariate logistic regression analyses using a bootstrapping method were performed.
  
  
  RESULTS
  At 3 years, toxicity scores of 436 patients were available. Grade ≥ 2 fibrosis in the boost area was observed in 8.5%, non-boost fibrosis in 49.4%, pain to the chest wall in 6.7%, and fair/poor CO in 39.7% of cases. Radiotherapy before chemotherapy was significantly associated with grade ≥ 2 boost fibrosis at 3 years (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.3-6.0). Non-boost fibrosis was associated with re-resection (OR 2.2, 95% CI 1.2-4.0) and larger tumors (OR 1.1, 95% CI 1.0-1.1). At 1 year, chest wall pain was significantly associated with high boost dosage (OR 2.1, 95% CI 1.2-3.7) and younger age (OR 0.4, 95% CI 0.2-0.7). A fair/poor CO was observed more often after re-resection (OR 4.5, 95% CI 2.4-8.5), after regional radiotherapy (OR 2.9, 95% CI 1.2-7.1), and in larger tumors (OR 1.1, 95% CI 1.0-1.1).
  
  
  CONCLUSIONS
  Toxicity and CO are not impaired after 3D-CRT-SIB. Fibrosis was not significantly associated with radiotherapy parameters. Independent risk factors for fibrosis were chemotherapy after radiotherapy, re-resection, and larger tumor size. Re-resection was most predictive for worse CO. Age had an impact on chest wall pain occurrence.
authors.affiliation: Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Enja J
authors.initials: EJ
authors.lastname: Bantema-Joppe
authors.forename: Cornelis
authors.initials: C
authors.lastname: Schilstra
authors.forename: Geertruida H
authors.initials: GH
authors.lastname: de Bock
authors.forename: Wil V
authors.initials: WV
authors.lastname: Dolsma
authors.forename: Dianne M
authors.initials: DM
authors.lastname: Busz
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Langendijk
authors.forename: John H
authors.initials: JH
authors.lastname: Maduro
mesh_terms: D000367:Age Factors; D000970:Antineoplastic Agents / Q000009:adverse effects; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D019583:Dose Fractionation, Radiation; D004954:Esthetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015412:Mastectomy, Segmental / Q000379:methods*; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D011832:Radiation Injuries / Q000473:pathology; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D012044:Regression Analysis; D019233:Retreatment; D012307:Risk Factors; D047368:Tumor Burden
chemical_list: D000970:Antineoplastic Agents