title: Can intensity-modulated radiation therapy spare the central flapped area while encompassing the target volume in radiotherapy after immediate breast reconstruction?
abstract: BACKGROUND
  Radiotherapy increases the morbidity of immediate breast reconstruction. To spare the flapped area without an adverse dose distribution of the target volume and organ at risks, various radiation techniques were assessed.
  
  
  METHODS
  Twelve breasts undergoing skin-sparing mastectomy and immediate transverse rectus abdominis myocutaneous flap reconstruction were evaluated. After a delineation of whole breast, the doughnut-like breast target volume (BTV) including the chest wall and skin and the subtracted central flapped volume (FV) were defined. The opposed wedge tangential radiotherapy (3-dimensional conformal radiotherapy (3-D CRT) ), field-in-field radiotherapy (FiF), inverse intensity-modulated radiotherapy (iIMRT), volumetric modulated arc radiotherapy (VMRT) and the mixture of FiF and iIMRT (HYBRID) were tried. Total 50 Gy was prescribed to the BTV. The paired student t-tests were performed.
  
  
  RESULTS
  The V47.5Gy of the BTV was improved in iIMRT and VMRT compared with 3-D CRT and FiF. The mean FV doses in iIMRT and VMRT were 76.7 ± 3.9% and 85.5 ± 4.0%, respectively. However the mean ipsilateral lung doses were aggravated by iIMRT and VMRT. In terms of HYBRID, the V47.5Gy for the BTV was 97.5 ± 0.7%. The mean FV dose was 89.4 ± 2.1%. While the mean FV dose in HYBRID was 13.7 ± 2.1% (P < 0.001) lower than FiF, it was 12.8 ± 1.9% (P < 0.001) higher than iIMRT. The mean ipsilateral lung dose in HYBRID was 2.8 ± 1.9% (P < 0.001) worse than FiF, and 2.6 ± 1.8% (P < 0.001) better than iIMRT.
  
  
  CONCLUSIONS
  The HYBRID could minimise the adverse dose distribution of lung and reduce 10% of the mean dose to the flapped area. For patients with adverse factors for the failure of breast reconstruction, the HYBRID could be considered.
authors.affiliation: Department of Radiation Oncology, Ansan Hospital, Korea University Medical Center, Ansan, Republic of Korea.
authors.forename: Jung Ae
authors.initials: JA
authors.lastname: Lee
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Yoon
authors.forename: Se Young
authors.initials: SY
authors.lastname: Chung
authors.forename: Dae Sik
authors.initials: DS
authors.lastname: Yang
authors.forename: Suk
authors.initials: S
authors.lastname: Lee
authors.forename: Young Je
authors.initials: YJ
authors.lastname: Park
authors.forename: Chul Yong
authors.initials: CY
authors.lastname: Kim
authors.forename: Gil Soo
authors.initials: GS
authors.lastname: Son
authors.forename: Eul Sik
authors.initials: ES
authors.lastname: Yoon
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D016462:Mammaplasty / Q000379:methods*; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D059351:Organ Sparing Treatments / Q000379:methods*; D058958:Organs at Risk / Q000000981:diagnostic imaging / Q000528:radiation effects; D020266:Radiotherapy, Conformal / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: breast cancer; breast reconstruction; intensity-modulated radiation therapy; organ at risk; target volume