Systematic quantitative evaluation of Plan-IQ for intensity-modulated radiation therapy after modified radical mastectomy

Kunzhi Chen,Xin Jiang,Lijuan Ding,Wenming Xia,Zhuangzhuang Zheng,Na Tao,Huidong Wang,Libo Wang

doi:10.1038/s41598-021-01305-3

Kunzhi Chen, Xin Jiang + Show 6 more

Open Access

https://doi.org/10.1038/s41598-021-01305-3

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Abstract

Radiotherapy (RT) is one of the main treatment strategies of breast cancer. It is challenging to design RT plans that can completely cover the target area while protecting organs at risk (OAR). The Plan-IQ feasibility tool can estimate the best sparing dose of OAR before optimizing the Plan. A systematic quantitative evaluation of the quality change of intensity-modulated radiation therapy (IMRT) using the Plan-IQ feasibility tool was performed for modified radical mastectomy in this study. We selected 50 patients with breast cancer treated with IMRT. All patients received the same dose in the planning target volume (PTV). The plans are categorized into two groups, with each patient having one plan in each group: the clinically accepted normal plan group (NP group) and the repeat plan group (RP group). An automated planning strategy was generated using a Plan-IQ feasibility dose volume histogram (FDVH) in RP group. These plans were assessed according to the dosimetry parameters. A detailed scoring strategy was based on the RTOG9804 report and 2018 National Comprehensive Cancer Network guidelines, combined with clinical experience. PTV coverage in both groups was achieved at 100% of the prescribed dose. Except for the thyroid coverage, the dose limit of organs at risk (OAR) in RP group was significantly better than that in NP group. In the scoring analysis, the total scores of RP group decreased compared to that of NP group (P < 0.05), and the individual scores of PTV and OAR significantly changed. PTV scores in RP group decreased (P < 0.01); however, OAR scores improved (P < 0.01). The Plan-IQ FDVH was useful for evaluating a class solution for IMRT planning. Plan-IQ can automatically help physicians design the best OAR protection plan, which sacrifices part of PTV, but still meets clinical requirements.

Highlights

Radiotherapy (RT) is one of the main treatment strategies of breast cancer
Plan-IQ can predict organs at risk (OAR) dose using a model that takes a 3-dimension dose clouds built outside targets as a benchmark to reflect the properties of radiation distribution observed in the media, which is computed using a series of energy-specific dose spread c alculations[13,14,15]
planning target volume (PTV) in both groups that were irradiated at 100% of the prescribed dose approached 50 Gy

Summary

Introduction

Radiotherapy (RT) is one of the main treatment strategies of breast cancer. It is challenging to design RT plans that can completely cover the target area while protecting organs at risk (OAR). A systematic quantitative evaluation of the quality change of intensity-modulated radiation therapy (IMRT) using the Plan-IQ feasibility tool was performed for modified radical mastectomy in this study. An automated planning strategy was generated using a Plan-IQ feasibility dose volume histogram (FDVH) in RP group. According to the recommendations of the National Comprehensive Cancer Network (NCCN) and Radiation Therapy Oncology Group (RTOG), patients with high risks of local recurrence need RT after mastectomy. IMRT can improve the tumor control rate and patient survival by increasing the dose in the target area and reducing the dose to organs at risk (OAR)[6,7,8]. When designing the RT plan, we sought to minimize the dose to the normal tissues and optimize the prescribed dose coverage, homogeneity, and conformal degree of the area (planning target volume (PTV)). The systematic quantification of FDVH was used to describe the changes in plan-IQ on the quality of IMRT plans

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Conclusion