The UK HeartSpare Study (Stage IB): randomised comparison of a voluntary breath-hold technique and prone radiotherapy after breast conserving surgery.
OBJECTIVE
To compare mean heart and left anterior descending coronary artery (LAD) doses (NTDmean) and positional reproducibility in larger-breasted women receiving left breast radiotherapy using supine voluntary deep-inspiratory breath-hold (VBH) and free-breathing prone techniques.


METHODS
Following surgery for early breast cancer, patients with estimated breast volumes >750 cm(3) underwent planning-CT scans in supine VBH and free-breathing prone positions. Radiotherapy treatment plans were prepared, and mean heart and LAD doses were calculated. Patients were randomised to receive one technique for fractions 1-7, before switching techniques for fractions 8-15 (40 Gy/15 fractions total). Daily electronic portal imaging and alternate-day cone-beam CT (CBCT) imaging were performed. The primary endpoint was the difference in mean LAD NTDmean between techniques. Population systematic (Σ) and random errors (σ) were estimated. Within-patient comparisons between techniques used Wilcoxon signed-rank tests.


RESULTS
34 patients were recruited, with complete dosimetric data available for 28. Mean heart and LAD NTDmean doses for VBH and prone treatments respectively were 0.4 and 0.7 (p<0.001) and 2.9 and 7.8 (p<0.001). Clip-based CBCT errors for VBH and prone respectively were ⩽3.0 mm and ⩽6.5 mm (Σ) and ⩽3.5 mm and ⩽5.4 mm (σ).


CONCLUSIONS
In larger-breasted women, supine VBH provided superior cardiac sparing and reproducibility than a free-breathing prone position.
Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton, UK. Electronic address: frederick.bartlett@rmh.nhs.uk.
Frederick R
FR
Bartlett
Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, UK.
Ruth M
RM
Colgan
Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, UK.
Ellen M
EM
Donovan
Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton, UK.
Helen A
HA
McNair
Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton, UK.
Karen
K
Carr
Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, UK; Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, UK.
Philip M
PM
Evans
Clinical Trials and Statistics Unit (ICR-CTSU), Institute of Cancer Research, London, UK.
Clare
C
Griffin
Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton, UK.
Imogen
I
Locke
Clinical Trials and Statistics Unit (ICR-CTSU), Institute of Cancer Research, London, UK.
Joanne S
JS
Haviland
Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, UK.
John R
JR
Yarnold
Department of Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton, UK.
Anna M
AM
Kirby
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D062485:Breath Holding; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003331:Coronary Vessels / Q000528:radiation effects; D005260:Female; D006321:Heart / Q000528:radiation effects; D006801:Humans; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D056888:Patient Positioning / Q000379:methods; D016684:Prone Position; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012509:Sarcoma / Q000209:etiology; D016683:Supine Position; D014057:Tomography, X-Ray Computed
Breast cancer; Breath-hold; Cardiac dose; Prone; Radiotherapy