title: Simultaneous integrated boost in breast conserving treatment of breast cancer: a dosimetric comparison of helical tomotherapy and three-dimensional conformal radiotherapy.
abstract: OBJECTIVE
  To evaluate the dosimetry of helical tomotherapy (HT) and three-dimensional conformal radiotherapy (3D-CRT) in breast cancer patients undergoing whole breast radiation with simultaneous integrated boost (SIB) of the tumor bed.
  
  
  METHODS
  Thirteen patients with breast cancer treated by lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned using both HT and 3D-CRT using the field-in-field technique. The whole breast and tumor bed were prescribed 50.68 Gy and 64.4 Gy, respectively, in 28 fractions. Dosimetries for both techniques were compared.
  
  
  RESULTS
  Coverage of the whole breast was adequate with both techniques (V(95%)=96.22% vs. 96.25%, with HT and 3D-CRT, respectively; p=0.64). Adequate tumor bed coverage was also achieved, although it was significantly lower with HT (V(95%)=97.18% vs. 99.72%; p<0.001). Overdose of the breast volume outside the tumor bed was significantly lower with HT (V(54.23 Gy)=12.47% vs. 30.83%; p<0.001). Ipsilateral lung V(20 Gy) (6.34% vs. 10.17%; p<0.001), V(5 Gy) (16.54% vs. 18.53%; p<0.05) and mean dose (4.05 Gy vs. 6.36 Gy; p<0.001) were significantly lower with HT. In patients with left-sided tumors, heart V(30 Gy) (0.03% vs. 1.14%; p<0.05) and mean dose (1.35 Gy vs. 2.22 Gy; p<0.01) were significantly lower with HT, but not V(5 Gy). Contralateral breast V(5 Gy) (0.27% vs. 0.00%; p<0.01) and maximum dose were significantly increased with HT.
  
  
  CONCLUSIONS
  In breast cancer treated with SIB, both HT and 3D-CRT provided adequate target volume coverage and low heart doses. Tumor bed coverage was slightly lower with HT, but HT avoided unnecessary breast overdosage while improving ipsilateral lung dosimetry.
authors.affiliation: Department of Radiation Oncology, Institut Curie, Paris, France. tarekhijal@hotmail.com
authors.forename: Tarek
authors.initials: T
authors.lastname: Hijal
authors.forename: Nathalie
authors.initials: N
authors.lastname: Fournier-Bidoz
authors.forename: Pablo
authors.initials: P
authors.lastname: Castro-Pena
authors.forename: Youlia M
authors.initials: YM
authors.lastname: Kirova
authors.forename: Sophia
authors.initials: S
authors.lastname: Zefkili
authors.forename: Marc A
authors.initials: MA
authors.lastname: Bollet
authors.forename: Rémi
authors.initials: R
authors.lastname: Dendale
authors.forename: François
authors.initials: F
authors.lastname: Campana
authors.forename: Alain
authors.initials: A
authors.lastname: Fourquet
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed