Background: Breast cancer is the most common cancer diagnosed
worldwide, synchronous bilateral breast cancer accounts for unique entity of the disease, particularly
post-operative radiotherapy for Synchronous Bilateral Breast Cancer (SBBC) is
challenging with lack of evidence about
the best irradiation technique. In this study, we tried to explore the optimum radiotherapy
technique regarding the dosimetric parameters. Methods: We recruited 15
SBBC patients in whom post-operative radiotherapy was indicated and we established three plans for each patient
using 3DCRT, IMRT and VMAT, and then we
compared the three plans as regard target volume coverage parameters and organs
at risk (OAR) doses. Results: We found that PTV coverage parameter was
superior with IMRT compared with 3DCRT and VMAT in terms of Dmean (p = 0.001),
D95% (p = 0.001), Dmax (p = 0.0001), conformity index (p = 0.0001) and
HI (p = 0.0001). Doses to OAR were not significantly different between the three
techniques in cardiac dose and LAD
maximum dose, but 3DCRT was superior in LAD mean dose (p = 0.03) and lung
volume receiving 20 Gy (V20) and 10 Gy (V10) (p = 0.0001), but this difference
was non-significant between 3DCRT and IMRT (p = 0.4 and 0.06 respectively),
while VMAT led to the highest doses to LAD and lung. Conclusions: IMRT
showed the best target coverage parameters in post-operative
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