TITLE:
Benefits and Limitations of Volumetric Modulated Arc Therapy in Treating Bilateral Breast Cancer with Regional Lymph Nodes
AUTHORS:
R. P. Srivastava, K. Vandeputte, C. De Wagter
KEYWORDS:
Bilateral Breast Cancer (BCC), Volumetric Modulated Arc Therapy (VMAT), Field in Field (FiF), Planning Target Volume (PTV), Organ’s Volume That Receives x Gy of Dose (VxGy)
JOURNAL NAME:
Advances in Breast Cancer Research,
Vol.9 No.4,
October
10,
2020
ABSTRACT: Purpose: The study was performed comparing dosimetric characteristics of
volumetric modulated arc therapy (VMAT) and field-in-field (FiF) techniques on
a patient with synchronous bilateral breast carcinoma. Methods: The
patients with bilateral breast cancer treatment were included in this study. A
total dose of 40.05 Gy in 15 fractions was prescribed to the Planning Target
Volume (PTV) of the whole bilateral breast cancer with the supraclavicular and
infraclavicular nodes, with a complementary boost of 10 Gy in 4 fractions to
the surgical bed (PTVboost). For both radiotherapy techniques,
several VxGy parameters were analyzed for the PTVs, together with
the Conformity index (CI), the Homogeneity index (HI) and the critical organs
at risk (OARs), lungs and heart. Results: The patient was treated by the
VMAT technique and the daily treatment time was less than 20 minutes with daily
CBCT imaging. In the VMAT plan, the PTV 95% dose covered 38.89 ± 0.81 Gy,
compared to 37.26 ± 1.02 Gy in the FiF technique. The VMAT plan improved the
dose homogeneity index and lower dose in lung towards high dose region. Conclusion: The study demonstrates the viability of the VMAT technique in the treatment of
bilateral breast cancer. The introduced single isocentric VMAT technique is
fast to deliver and it increases the dose homogeneity of the target volume with
some limitations. The treatment was well tolerated, without interruption of the
treatment courses caused by treatment-related toxicities.