title: A new three-dimensional conformal radiotherapy (3DCRT) technique for large breast and/or high body mass index patients: evaluation of a novel fields assessment aimed to reduce extra-target-tissue irradiation.
abstract: OBJECTIVE
  To develop an alternative three-dimensional treatment plan with standardized fields class solution for whole-breast radiotherapy in patients with large/pendulous breast and/or high body mass index (BMI).
  
  
  METHODS
  Two treatment plans [tangential fields and standardized five-fields technique (S5F)] for a total dose of 50 Gy/25 fractions were generated for patients with large breasts [planning target volume (PTV) >1000 cm(3) and/or BMI >25 kg m(-2)], supine positioned. S5F plans consist of two wedged tangential beams, anteroposterior: 20° for the right breast and 340° for the left breast, and posteroanterior: 181° for the right breast and 179° for the left breast. A field in field in medial-lateral beam and additional fields were added to reduce hot spot areas and extra-target-tissue irradiation and to improve dose distribution. The percentage of PTV receiving 95% of the prescribed dose (PTV V95%), percentage of PTV receiving 105% of the prescribed dose (PTV V105%), maximal dose to PTV (PTV Dmax), homogeneity index (HI) and conformity index were recorded. V10%, V20%, V105% and V107% of a "proper" normal tissue structure (body-PTV healthy tissue) were recorded. Statistical analyses were performed using SYSTAT v.12.0 (SPSS, Chicago, IL).
  
  
  RESULTS
  In 38 patients included, S5F improved HI (8.4 vs 10.1; p ≤ 0.001) and significantly reduced PTV Dmax and PTV V105%. The extra-target-tissue irradiation was significantly reduced using S5F for V105% (cm(3)) and V107% (cm(3)) with a very high difference in tissue irradiation (46.6 vs 3.0 cm(3), p ≤ 0.001 for V105% and 12.2 vs 0.0 cm(3), p ≤ 0.001 for V107% for tangential field and S5F plans, respectively). Only a slight increase in low-dose extra-target-tissue irradiation (V10%) was observed (2.2719 vs 1.8261 cm(3), p = 0.002).
  
  
  CONCLUSIONS
  The S5F technique in patients with large breast or high BMI increases HI and decreases hot spots in extra-target-tissues and can therefore be easily implemented in breast cancer radiotherapy.
  
  
  CONCLUSIONS
  The treatment planning strategy proposed in this study has several advantages: (a) it is extremely reliable as the standard supine positioning is used; (b) the standardized class solution allows for widespread use;
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Stimato
authors.initials: S
authors.lastname: Gerardina
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Ippolito
authors.initials: I
authors.lastname: Edy
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Silipigni
authors.initials: S
authors.lastname: Sonia
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Di Venanzio
authors.initials: DV
authors.lastname: Cristina
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Rinaldi
authors.initials: R
authors.lastname: Carla Germana
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Gaudino
authors.initials: G
authors.lastname: Diego
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Fiore
authors.initials: F
authors.lastname: Michele
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Trodella
authors.initials: T
authors.lastname: Lucio
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: D'Angelillo Rolando
authors.initials: DR
authors.lastname: Maria
authors.affiliation: Radiotherapy Unit, Campus Bio-Medico University, Rome, Italy.
authors.forename: Ramella
authors.initials: R
authors.lastname: Sara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001940:Breast / Q000002:abnormalities*; D001943:Breast Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000150:complications*; D015412:Mastectomy, Segmental / Q000379:methods*; D008875:Middle Aged; D059351:Organ Sparing Treatments / Q000379:methods; D058958:Organs at Risk; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*