title: Unintended irradiation of internal mammary chain - Is that enough?
abstract: OBJECTIVE
  To evaluate the unintentional coverage of the internal mammary chain (IMC) with tangential fields irradiation to the breast, and its relation with the type of surgery employed.
  
  
  BACKGROUND
  The dose distribution in regions adjacent to the treatment targets (mammary gland or chest wall), with incidental irradiation of the IMC, could translate into clinical benefit, due to the proximity of these regions.
  
  
  METHODS
  One hundred and twelve consecutive conformal radiotherapy plans were correlating the average dose to the IMC with the type of surgery employed, the extent of disease and the irradiation techniques.
  
  
  RESULTS
  The mean doses to IMC after modified radical mastectomy (MRM), modified radical mastectomy with immediate reconstruction (MRM + R), and breast conservative surgery (BCS) were 30.34 Gy, 30.26 Gy, and 18.67 Gy, respectively. Significant differences were identified between patients who underwent MRM or MRM + R over BCS (p = 0.01 and 0.003, respectively), but not between MRM and MRM + R (p = 0.88). Mean doses to IMC were greater in patients with T3-T4 tumors when compared with more initial stages (≤T2) (p = 0.0096). The lymph node involvement also correlated with higher average doses to IMC (node positive: 26.1 Gy × node negative: 17.8 Gy, p = 0.0017).
  
  
  CONCLUSIONS
  The moderate dose level to the IMC in the unintentional irradiation scenario seems to be insufficient to treat the subclinical disease, although it could have an impact in patients undergoing mastectomy.
authors.affiliation: Instituto COI, MD.X Barra Medical Center, Av. das Américas, 6.205 Loja E - Barra da Tijuca, 22793-080 Rio de Janeiro, Brazil; Antonio Cândido Camargo Cancer Center - ACCCC, R. Professor Antônio Prudente, 211 - Liberdade, São Paulo, SP CEP 01509-010, Brazil.
authors.forename: Lucas Gomes
authors.initials: LG
authors.lastname: Sapienza
authors.affiliation: Antonio Cândido Camargo Cancer Center - ACCCC, R. Professor Antônio Prudente, 211 - Liberdade, São Paulo, SP CEP 01509-010, Brazil.
authors.forename: Michael Jenwei
authors.initials: MJ
authors.lastname: Chen
authors.affiliation: Hospital Federal Servidores do Estado do Rio de Janeiro - HFSE, Rua Sacadura Cabral, 178, CEP 20221-903 Rio de Janeiro, RJ, Brazil.
authors.forename: Maria José Leite
authors.initials: MJ
authors.lastname: Gomes
authors.affiliation: U.H. Seidman Cancer Cente, 11100 Euclid Ave., Cleveland, OH 44106, United States.
authors.forename: David B
authors.initials: DB
authors.lastname: Mansur
keywords: 3DCRT; Breast cancer; Internal mammary chain; Radiotherapy; Unintentional irradiation