title: Breast radiotherapy (RT) using tangential fields (TgF): a prospective evaluation of the dose distribution in the sentinel lymph node (SLN) area as determined intraoperatively by clip placement.
abstract: BACKGROUND
  Randomized trials have established that patients with limited involvement of sentinel lymph node (SLN) do not require axillary lymph node dissection (ALND). The similar outcome in patients with ≤2 positive SLN with or without additional ALND is attributed, in part, to tangential fields (TgF) RT. We evaluated the dose distribution in the SLN biopsy area (SLNBa) as determined intraoperatively by clips placement for radiotherapy (RT) optimization.
  
  
  METHODS
  This prospective study included 25 patients who had breast conservation. Titanium clips were used intraoperatively to mark the SLNBa. All patients had 3D-conformal RT using standard (STgF) or high tangential fields (HTgF). Axillary levels, SLNBa, and organs at risk were contoured on a CT scan. Dose distribution and overlap between TgF and target volumes were analyzed.
  
  
  RESULTS
  The average doses delivered to axilla levels I-III and SLNBa were 25, 5, 2, and 33 Gy, respectively. The average dose delivered to SLNBa was higher using HTgF with better coverage of the axilla. Only 12 of 25 patients (48 %) had their SLNBa completely covered by the TgF. There was no impact of TgF size on ipsilateral lung dose. The mean heart dose delivered using STgF was lower than HTgF.
  
  
  CONCLUSIONS
  In the era of SLNB, axilla and SNLBa RT technique has to be standardized to deliver adequate dose. We recommend the use of HTgF or direct axillary RT techniques (such as in AMAROS trial) in patients with metastases in SLN without ALND completion, when only TgF are expected to cure potential residual disease in the axilla.
authors.affiliation: AP-HP, GH Henri Mondor. Service d'Oncologie-Radiothérapie et Centre Sein Henri Mondor. Université Paris-Est Créteil (UPEC), Créteil, France, yazid.belkacemi@hmn.aphp.fr.
authors.forename: Yazid
authors.initials: Y
authors.lastname: Belkacemi
authors.forename: Veronique
authors.initials: V
authors.lastname: Bigorie
authors.forename: Qiong
authors.initials: Q
authors.lastname: Pan
authors.forename: Ryan
authors.initials: R
authors.lastname: Bouaita
authors.forename: Frederic
authors.initials: F
authors.lastname: Pigneur
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Itti
authors.forename: Hakima
authors.initials: H
authors.lastname: Badaoui
authors.forename: Elias
authors.initials: E
authors.lastname: Assaf
authors.forename: Philippe
authors.initials: P
authors.lastname: Caillet
authors.forename: Elie
authors.initials: E
authors.lastname: Calitchi
authors.forename: Romain
authors.initials: R
authors.lastname: Bosc
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018275:Carcinoma, Lobular / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D058958:Organs at Risk; D011379:Prognosis; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D021701:Sentinel Lymph Node Biopsy; D013525:Surgical Instruments
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