Retrospective methods to estimate radiation dose at the site of breast cancer development after Hodgkin lymphoma radiotherapy.

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Publication Date
2017-12ICR Author
Author
Russell, NS
Krul, IM
van Eggermond, AM
Aleman, BMP
Cooke, R
Kuiper, S
Allen, SD
Wallis, MG
Llanas, D
Diallo, I
de Vathaire, F
Smith, SA
Hauptmann, M
Broeks, A
Swerdlow, AJ
Van Leeuwen, FE
Type
Journal Article
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Show full item recordAbstract
Background:An increased risk of breast cancer following radiotherapy for Hodgkin lymphoma (HL) has now been robustly established. In order to estimate the dose-response relationship more accurately, and to aid clinical decision making, a retrospective estimation of the radiation dose delivered to the site of the subsequent breast cancer is required. Methods:For 174 Dutch and 170 UK female patients with breast cancer following HL treatment, the 3-dimensional position of the breast cancer in the affected breast was determined and transferred onto a CT-based anthropomorphic phantom. Using a radiotherapy treatment planning system the dose distribution on the CT-based phantom was calculated for the 46 different radiation treatment field set-ups used in the study population. The estimated dose at the centre of the breast cancer, and a margin to reflect dose uncertainty were determined on the basis of the location of the tumour and the isodose lines from the treatment planning. We assessed inter-observer variation and for 47 patients we compared the results with a previously applied dosimetry method. Results:The estimated median point dose at the centre of the breast cancer location was 29.75 Gy (IQR 5.8-37.2), or about 75% of the prescribed radiotherapy dose. The median dose uncertainty range was 5.97 Gy. We observed an excellent inter-observer variation (ICC 0.89 (95% CI: 0.74-0.95)). The absolute agreement intra-class correlation coefficient (ICC) for inter-method variation was 0.59 (95% CI: 0.37-0.75), indicating (nearly) good agreement. There were no systematic differences in the dose estimates between observers or methods. Conclusion:Estimates of the dose at the point of a subsequent breast cancer show good correlation between methods, but the retrospective nature of the estimates means that there is always some uncertainty to be accounted for.
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Licenseref URL
http://creativecommons.org/licenses/by/4.0/Version of record
Research team
Aetiological Epidemiology
Language
eng
Date accepted
2017-09-16
License start date
2017-12
Citation
Clinical and translational radiation oncology, 2017, 7 pp. 20 - 27