Adjuvant Radiotherapy after Breast Conserving Treatment for Breast Cancer:A Dosimetric Comparison between Volumetric Modulated Arc Therapy and Intensity Modulated Radiotherapy

Zhe-Ming Liu,Liang-Liang Zhan,Qin Qin,Li-Ping Xu,Xiao-Lin Ge,Xin-Chen Sun,Pei-Pei Wang,Jing Lu,Hong-Cheng Zhu,Chi Zhang,Hong-Yan Cheng,Jia Liu,Xi Yang,Jia-Yan Chen

doi:10.7314/apjcp.2015.16.8.3257

Zhe-Ming Liu, Liang-Liang Zhan + Show 12 more

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https://doi.org/10.7314/apjcp.2015.16.8.3257

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Abstract

Radiotherapy is an important treatment of choice for breast cancer patients after breast- conserving surgery, and we compare the feasibility of using dual arc volumetric modulated arc therapy (VMAT2), single arc volumetric modulated arc therapy (VMAT1) and Multi-beam Intensity Modulated Radiotherapy (M-IMRT) on patients after breast-conserving surgery. Thirty patients with breast cancer (half right-sided and half left-sided) treated by conservative lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned with three different radiotherapy techniques: 1) VMAT1; 2) VMAT2; 3) M-IMRT. The distributions for the planning target volume (PTV) and organs at risk (OARs) were compared. Dosimetries for all the techniques were compared. All three techniques satisfied the dose constraint well. VMAT2 showed no obvious difference in the homogeneity index (HI) and conformity index (CI) of the PTV with respect to M-IMRT and VMAT1. VMAT2 clearly improved the treatment efficiency and can also decrease the mean dose and V5Gy of the contralateral lung. The mean dose and maximum dose of the spinal cord and contralateral breast were lower for VMAT2 than the other two techniques. The very low dose distribution (V1Gy) of the contralateral breast also showed great reduction in VMAT2 compared with the other two techniques. For the ipsilateral lung of right-sided breast cancer, the mean dose was decreased significantly in VMAT2 compared with VMAT1 and M-IMRT. The V20Gy and V30Gy of the ipsilateral lung of the left- sided breast cancer for VMAT2 showed obvious reduction compared with the other two techniques. The heart statistics of VMAT2 also decreased considerably compared to VMAT1 and M-IMRT. Compared to the other two techniques, the dual arc volumetric modulated arc therapy technique reduced radiation dose exposure to the organs at risk and maintained a reasonable target dose distribution.

Highlights

During the past several years, the incidence of breast cancer in Asia has increased at an unbelievable rate (McCormack et al, 2011)
Radiotherapy is an important treatment of choice for breast cancer patients after breastconserving surgery, and we compare the feasibility of using dual arc volumetric modulated arc therapy (VMAT2), single arc volumetric modulated arc therapy (VMAT1) and Multi-beam Intensity Modulated Radiotherapy (M-IMRT) on patients after breast-conserving surgery
Materials and Methods: Thirty patients with breast cancer treated by conservative lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned with three different radiotherapy techniques: 1) VMAT1; 2) VMAT2; 3) M-IMRT

Summary

Introduction

During the past several years, the incidence of breast cancer in Asia has increased at an unbelievable rate (McCormack et al, 2011). The investigation of SIB has been used to improve dose conformity to the boost volume as well as to decrease doses to the heart, lungs, and many other organs at risk when incorporated with either VMAT or IMRT, compared with a sequential boost (Hurkmans et al, 2006; Singla et al, 2006; van der Laan et al, 2007). It has the advantage of reducing the overall number of control points for the patient. Conclusions: Compared to the other two techniques, the dual arc volumetric modulated arc therapy technique reduced radiation dose exposure to the organs at risk and maintained a reasonable target dose distribution

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