Planning with intensity-modulated radiotherapy and tomotherapy to modulate dose across breast to reflect recurrence risk (IMPORT High trial).
OBJECTIVE
To establish planning solutions for a concomitant three-level radiation dose distribution to the breast using linear accelerator- or tomotherapy-based intensity-modulated radiotherapy (IMRT), for the U.K. Intensity Modulated and Partial Organ (IMPORT) High trial.


METHODS
Computed tomography data sets for 9 patients undergoing breast conservation surgery with implanted tumor bed gold markers were used to prepare three-level dose distributions encompassing the whole breast (36 Gy), partial breast (40 Gy), and tumor bed boost (48 or 53 Gy) treated concomitantly in 15 fractions within 3 weeks. Forward and inverse planned IMRT and tomotherapy were investigated as solutions. A standard electron field was compared with a photon field arrangement encompassing the tumor bed boost volume. The out-of-field doses were measured for all methods.


RESULTS
Dose-volume constraints of volume >90% receiving 32.4 Gy and volume >95% receiving 50.4 Gy for the whole breast and tumor bed were achieved. The constraint of volume >90% receiving 36 Gy for the partial breast was fulfilled in the inverse IMRT and tomotherapy plans and in 7 of 9 cases of a forward planned IMRT distribution. An electron boost to the tumor bed was inadequate in 8 of 9 cases. The IMRT methods delivered a greater whole body dose than the standard breast tangents. A contralateral lung volume >2.5 Gy was increased in the inverse IMRT and tomotherapy plans, although it did not exceed the constraint.


CONCLUSIONS
We have demonstrated a set of widely applicable solutions that fulfilled the stringent clinical trial requirements for the delivery of a concomitant three-level dose distribution to the breast.
Donovan
Ellen M
EM
Physics Department, Royal Marsden Foundation Trust, Sutton, Surrey, United Kingdom. ellen.donovan@icr.ac.uk
Ciurlionis
Laura
L
Fairfoul
Jamie
J
James
Hayley
H
Mayles
Helen
H
Manktelow
Sophie
S
Raj
Sanjay
S
Tsang
Yat
Y
Tywman
Nicola
N
Yarnold
John
J
Coles
Charlotte
C
D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000517:prevention & control* / Q000532:radiotherapy*; D004583:Electrons / Q000627:therapeutic use; D005260:Female; D057918:Fiducial Markers; D006321:Heart / Q000528:radiation effects; D006801:Humans; D008168:Lung / Q000528:radiation effects; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D017785:Photons / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D013819:Thermoluminescent Dosimetry / Q000379:methods; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden