title: Reduction of cardiac and coronary artery doses in irradiation of left-sided breast cancer during inspiration breath hold : A planning study.
abstract: OBJECTIVE
  The radiation dose received by the heart during adjuvant left-sided breast irradiation plays a crucial role in development of late toxicity. Although the absolute risk of cardiotoxicity can be reduced with modern irradiation techniques, cardiotoxic chemotherapy increases the risk of late damage. Thus, the radiation dose to the heart should be minimized. This study evaluated the influence of different amplitudes of inspiration breath hold (IBH) during simulated left-sided breast irradiation on cardiac doses compared to free breathing (FB).
  
  
  METHODS
  CT data of 11 lung cancer patients were retrospectively used as left-sided pseudo-breast cancer cases. Two CT scans were used, one during IBH and one during FB, and two treatment plans were generated. Relevant heart, lung, and left anterior descending artery (LAD) parameters were derived from dose-volume histograms. The normal tissue complication probabilities (NTCPs) for the heart were calculated based on the relative seriality model. Inspiration depth was quantified using chest volume and diameter, and correlated thereafter to a possible sparing of heart tissue.
  
  
  RESULTS
  Mean reduction of heart dose for IBH compared to FB was 40 % (1.65 vs. 0.99 Gy; p = 0.007). Maximum dose to the heart and LAD could be decreased by 33 % (p = 0.011) and 43 % (p = 0.024), respectively. The mean anteroposterior shift was 5 mm (range 0.9-9.5 mm). Significant negative correlations between the relative change in LAD mean dose and the mean thoracic diameter and volume change, as well as with the absolute change in thoracic diameter were seen. The NTCP for cardiac mortality could be decreased by about 78 % (p = 0.017).
  
  
  CONCLUSIONS
  For left-sided breast cancer patients, cardiac doses can be significantly decreased with tangential irradiation and IBH.
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schönecker
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Heinz
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Söhn
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Haimerl
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Corradini
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Pazos
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Belka
authors.affiliation: Department of Radiation Oncology, University Hospital of Ludwig-Maximilian-University, Ziemssenstr. 1, 80336, Munich, Germany. Heike.Scheithauer@med.uni-muenchen.de.
authors.forename: H
authors.initials: H
authors.lastname: Scheithauer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D062485:Breath Holding; D003331:Coronary Vessels / Q000528:radiation effects*; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D001239:Inhalation; D008297:Male; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D059351:Organ Sparing Treatments / Q000379:methods; D058958:Organs at Risk / Q000528:radiation effects; D000069079:Radiation Exposure / Q000032:analysis* / Q000517:prevention & control*; D011832:Radiation Injuries / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D000069584:Unilateral Breast Neoplasms / Q000532:radiotherapy*
keywords: Breast-conserving surgery; Cardiotoxicity; NTCP; Organs at risk; Radiotherapy