Minimum breast distance largely explains individual variability in doses to contralateral breast from breast-cancer radiotherapy

Pavel Kundrát; Julia Remmele; Hannes Rennau; Sabine Sebb; Cristoforo Simonetto; Markus Eidemüller; Ulrich Wolf; Guido Hildebrandt

doi:10.1016/j.radonc.2018.08.022

Minimum breast distance largely explains individual variability in doses to contralateral breast from breast-cancer radiotherapy

Radiother Oncol. 2019 Feb:131:186-191. doi: 10.1016/j.radonc.2018.08.022. Epub 2018 Sep 18.

Authors

Pavel Kundrát¹, Julia Remmele², Hannes Rennau³, Sabine Sebb⁴, Cristoforo Simonetto⁵, Markus Eidemüller⁶, Ulrich Wolf⁷, Guido Hildebrandt⁸

Affiliations

¹ Institute of Radiation Protection, Department of Radiation Sciences, Helmholtz Zentrum München, Neuherberg, Germany. Electronic address: [email protected].
² Department of Radiation Oncology, University Leipzig, Germany. Electronic address: [email protected].
³ Department of Radiation Oncology, University Rostock, Germany. Electronic address: [email protected].
⁴ Department of Radiation Oncology, University Rostock, Germany. Electronic address: [email protected].
⁵ Institute of Radiation Protection, Department of Radiation Sciences, Helmholtz Zentrum München, Neuherberg, Germany. Electronic address: [email protected].
⁶ Institute of Radiation Protection, Department of Radiation Sciences, Helmholtz Zentrum München, Neuherberg, Germany. Electronic address: [email protected].
⁷ Department of Radiation Oncology, University Leipzig, Germany. Electronic address: [email protected].
⁸ Department of Radiation Oncology, University Rostock, Germany. Electronic address: [email protected].

PMID: 30241788
DOI: 10.1016/j.radonc.2018.08.022

Abstract

Purpose: To provide personalized estimates of doses to contralateral breast (CB) from breast-cancer radiotherapy.

Methods: Whole-breast irradiations using 3D conformal, intensity-modulated and hybrid techniques with 50.4 Gy prescribed dose were planned for 128 breast-cancer patients. From their CT images, 17 anatomic measures were assessed and tested by model fitting as predictors for CB dose-volume characteristics.

Results: Multi-field intensity-modulated radiotherapy (IMRT) yielded mean CB doses of 0.8-7.1 Gy, with no correlation to the studied anatomic parameters. Tangential whole-breast irradiation led to much lower mean CB doses, 0.2-1.6 Gy. About 60% of this inter-patient variability was explained by individual variations in a single anatomic measure, the minimum breast distance (MBD), defined as the CB distance from the tangent to the treated breast. Per 1 cm increase in MBD, the mean CB dose decreased by 10-15%. As an alternative to MBD, dose estimates could be based on the breast-to-breast distance, which is highly correlated with MBD.

Conclusion: The results enable personalized assessment of CB doses from tangential whole-breast irradiation, based only on parameters assessable from CT data. This may help support clinical decision-making processes as well as analyse retrospective studies on CB risks.

Keywords: Anatomic parameters; Breast-cancer radiotherapy; Contralateral breast; Individual variability.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Breast / anatomy & histology*
Breast / diagnostic imaging
Breast / radiation effects*
Breast Neoplasms / diagnostic imaging
Breast Neoplasms / pathology
Breast Neoplasms / radiotherapy*
Female
Humans
Neoplasm Staging
Precision Medicine
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods*
Radiotherapy, Conformal / methods
Radiotherapy, Intensity-Modulated / methods
Retrospective Studies