Assessment of contralateral mammary gland dose in the treatment of breast cancer using accelerated hypofractionated radiotherapy.
OBJECTIVE
To measure the dose distribution, related to the treatment planning calculations, in the contralateral mammary gland of breast cancer patients treated with accelerated hypofractionated 3-dimensional conformal radiotherapy.


METHODS
Thirty-four prospectively selected female patients with right breast cancer (pN0, negative surgical margins) were treated with breast-conserving surgery. A total dose of 42.5 Gy (2.66 Gy/fraction) was prescribed; it was requested that planning target volumes be covered by the 95% isodose line. The contralateral mammary gland was defined on CT simulation. The dose received was evaluated by dose volume histograms.


RESULTS
The measured contralateral breast doses were: (1) Dose maximum: 290-448 cGy [Equivalent (Eq) 337-522 cGy]; (2) Mean dose: 45-70 cGy (Eq 524-815 cGy); and (3) Median dose: 29-47 cGy (337-547 cGy) for total primary breast dose of 42.5 Gy in 16 equal fractions. The spearman rho correlation showed statistical significance between the contralateral breast volume and maximum dose (P = 0.0292), as well as mean dose (P = 0.0025) and median dose (P = 0.046) to the breast.


CONCLUSIONS
Minimizing the dose to the contralateral breast has to be one of the priorities of the radiation oncologist when using short schedules because of the radiosensitivity of this organ at risk. Further study is necessary to assess the long-term clinical impact of this schedule.
Maria Tolia, Kalliopi Platoni, Andreas Foteineas, Maria-Aggeliki Kalogeridi, Anna Zygogianni, Maria Dilvoi, Panagiotis Pantelakos, John Kouvaris, Vassilis Kouloulias, 1st and 2nd Department of Radiology, Radiation Oncology Unit, Medical School, Athens 12462, Greece.
Maria
M
Tolia
Kalliopi
K
Platoni
Andreas
A
Foteineas
Maria-Aggeliki
MA
Kalogeridi
Anna
A
Zygogianni
Nikolaos
N
Tsoukalas
Mariangela
M
Caimi
Niki
N
Margari
Maria
M
Dilvoi
Panagiotis
P
Pantelakos
John
J
Kouvaris
Vassilis
V
Kouloulias