title: Axillary coverage by whole breast irradiation in 1 to 2 positive sentinel lymph nodes in breast cancer patients.
abstract: OBJECTIVE
  To evaluate the dosimetric coverage of axillary levels I, II, and III obtained with standard whole breast irradiation in 1 to 2 positive sentinel lymph nodes (SLNs) patients not submitted to axillary lymph nodes dissection (ALND), and to compare the lymph nodes areas coverage obtained with 3D conformal radiation therapy, intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT).
  
  
  METHODS
  Patients with 1 to 2 positive SLNs undergoing breast-conserving therapy, without ALND, were included in the analysis. For each patient, 3 treatment plans were performed: a 3D conventional tangential plan, a static IMRT plan, and a volumetric IMRT, designed to encompass the entire breast parenchyma. The volumes of axillary levels I, II, and III receiving 90% and 95% (V90, V95) of the whole breast prescribed dose were evaluated. Dose-volume histograms were compared by means of the Friedman test.
  
  
  RESULTS
  Ten patients were enrolled. All defined breast volumes received &gt;95% of the prescribed dose with the 3 techniques. Median V95 for axillary level I was 26.4% (range 4.7%-61.3%) for 3D plans, 8.6% (range 0.64%-19.1%) for static IMRT plans, and 2.6% (range 0.4%-4.7%) for volumetric IMRT plans (p&lt;0.001). Median V95 for axillary level II was 5.4% (range 0%-14.6%), 1.9% (range 0%-15%), and 2.6% (range 0.4%-4.7%) for 3D, static IMRT, and volumetric IMRT, respectively (p&lt;0.001).
  
  
  CONCLUSIONS
  Results of our analysis showed that standard 3D tangential whole breast irradiation failed to deliver a therapeutic dose to axillary levels I and II. The coverage was even lower using static and volumetric IMRT techniques.
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: De Santis
authors.affiliation: Medical Physics Unit, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bonfantini
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Dispinzieri
authors.affiliation: Medical Physics Unit, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Meroni
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Diletto
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Elisa D
authors.initials: ED
authors.lastname: Mantero
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Marzia
authors.initials: M
authors.lastname: Franceschini
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Fulvia
authors.initials: F
authors.lastname: Soncini
authors.affiliation: Oncology Department, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Di Cosimo
authors.affiliation: Medical Physics Unit, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Cosentino
authors.affiliation: Medical Physics Unit, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Pignoli
authors.affiliation: Radiotherapy Unit 1, National Cancer Institute of Milan, Milan - Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Lozza
mesh_terms: D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D000071036:Sentinel Lymph Node / Q000473:pathology*