title: Synchronous bilateral breast cancer irradiation: clinical and dosimetrical issues using volumetric modulated arc therapy and simultaneous integrated boost.
abstract: OBJECTIVE
  The aim of the present retrospective analysis was to evaluate dosimetric parameters, feasibility and outcome for Synchronous Bilateral Breast Cancer (SBBC) patients treated with adjuvant radiotherapy (RT) by Volumetric Modulated Arc Therapy (VMAT).
  
  
  METHODS
  From September 2011 to April 2016, 1100 Breast Cancer (BC) patients were referred to our institution to receive adjuvant breast RT, and those with SBBC were selected for the present analysis. A total of 16 patients were identified. A total dose of 50 Gy in 25 fractions was prescribed to the Planning Target Volume of the whole bilateral breast (PTVBN) with or without the supraclavicular and infraclavicular nodes, while a total dose of 60 Gy in 25 fractions was prescribed to the surgical bed (PTVboost). Several VxGyand Dx% parameters were analyzed for the PTVs, together with Conformity and Homogeneity indexes (CI, HI), and for the critical Organs at risk (OARs), lungs and heart first.
  
  
  RESULTS
  With a median follow-up of 24 months, no acute or late side effects more than grade 2 were observed. All patients are alive without any sign of disease. For target dose coverage, our observed inter-patients averages (±1 sd) were V95% Dp= 96.7 ± 1.6% (96.3 ± 1.8%) to the left (right) PTVBN, V95% Dp= 98.6 ± 2.7% (99.4 ± 0.9%) to the left (right) PTVboost, and D2%= 64.4 ± 1.8 Gy (65.0 ± 2.0 Gy) to the left (right) PTVboost, respectively. With regard to the heart, the inter-patient average of Dmeanwas 8.3 ± 3.3 Gy. For the lungs, the inter-patient average of Dmean, V5 Gyand V20 Gywere 11.8 ± 2.3 Gy, 78.9 ± 15.3% and 15.7 ± 5%, respectively.
  
  
  CONCLUSIONS
  The present retrospective analysis showed the feasibility, tolerability and safety of VMAT in the treatment of SBBC patients. Further studies are necessary to confirm these preliminary data.
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Alba
authors.initials: A
authors.lastname: Fiorentino
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy. rosariomazzola@hotmail.it.
authors.forename: Rosario
authors.initials: R
authors.lastname: Mazzola
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Naccarato
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Niccolò
authors.initials: N
authors.lastname: Giaj-Levra
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Fersino
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Gianluisa
authors.initials: G
authors.lastname: Sicignano
authors.affiliation: Radiation Oncology School, University of Padua, Padua, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Tebano
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ricchetti
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Ruggero
authors.initials: R
authors.lastname: Ruggieri
authors.affiliation: Radiation Oncology, Sacro Cuore Don Calabria Cancer Care Center, via Don Sempreboni 5, 37034, Negrar, Verona, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Alongi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012189:Retrospective Studies
keywords: Bilateral breast cancer; Breast radiotherapy; Nodal irradiation; Simultaneous integrated boost; VMAT