A multicentre study of the evidence for customized margins in photon breast boost radiotherapy.
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Authors
Harris, EJ
Mukesh, MB
Donovan, EM
Kirby, AM
Haviland, JS
Jena, R
Yarnold, J
Baker, A
Dean, J
Eagle, S
Mayles, H
Griffin, C
Perry, R
Poynter, A
Coles, CE
Evans, PM
IMPORT high trialists,
Mukesh, MB
Donovan, EM
Kirby, AM
Haviland, JS
Jena, R
Yarnold, J
Baker, A
Dean, J
Eagle, S
Mayles, H
Griffin, C
Perry, R
Poynter, A
Coles, CE
Evans, PM
IMPORT high trialists,
Document Type
Journal Article
Date
2016-01-01
Date Accepted
Abstract
OBJECTIVE: To determine if subsets of patients may benefit from smaller or larger margins when using laser setup and bony anatomy verification of breast tumour bed (TB) boost radiotherapy (RT). METHODS: Verification imaging data acquired using cone-beam CT, megavoltage CT or two-dimensional kilovoltage imaging on 218 patients were used (1574 images). TB setup errors for laser-only setup (dlaser) and for bony anatomy verification (dbone) were determined using clips implanted into the TB as a gold standard for the TB position. Cases were grouped by centre-, patient- and treatment-related factors, including breast volume, TB position, seroma visibility and surgical technique. Systematic (Σ) and random (σ) TB setup errors were compared between groups, and TB planning target volume margins (MTB) were calculated. RESULTS: For the study population, Σlaser was between 2.8 and 3.4 mm, and Σbone was between 2.2 and 2.6 mm, respectively. Females with larger breasts (p = 0.03), easily visible seroma (p ≤ 0.02) and open surgical technique (p ≤ 0.04) had larger Σlaser. Σbone was larger for females with larger breasts (p = 0.02) and lateral tumours (p = 0.04). Females with medial tumours (p < 0.01) had smaller Σbone. CONCLUSION: If clips are not used, margins should be 8 and 10 mm for bony anatomy verification and laser setup, respectively. Individualization of TB margins may be considered based on breast volume, TB and seroma visibility. ADVANCES IN KNOWLEDGE: Setup accuracy using lasers and bony anatomy is influenced by patient and treatment factors. Some patients may benefit from clip-based image guidance more than others.
Citation
The British journal of radiology, 2016, 89 (1058), pp. 20150603 - ?
Source Title
Publisher
BRITISH INST RADIOLOGY
ISSN
0007-1285
eISSN
1748-880X
Collections
Research Team
Clinical Trials & Statistics Unit
Breast Cancer Radiotherapy
Imaging for Radiotherapy Adaptation
Breast Cancer Radiotherapy
Imaging for Radiotherapy Adaptation