Dosimetric evaluation of different planning strategies for hypofractionated whole-breast irradiation technique

Chunbo Tang; Biaoshui Liu; Jun Yuan; Ji He; Ruilian Xie; Minfeng Huang; Shanzhou Niu; Hongdong Liu

doi:10.1088/1361-6560/ad4445

Dosimetric evaluation of different planning strategies for hypofractionated whole-breast irradiation technique

Phys Med Biol. 2024 Apr 26. doi: 10.1088/1361-6560/ad4445. Online ahead of print.

Authors

Chunbo Tang¹, Biaoshui Liu², Jun Yuan³, Ji He⁴, Ruilian Xie⁵, Minfeng Huang⁶, Shanzhou Niu⁷, Hongdong Liu⁸

Affiliations

¹ Department of Radiation Oncology, First Affiliated Hospital of Gannan Medical University, Ganzhou, jiangxi,ganzhou, 341000, CHINA.
² Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangzhou, Guangdong, 510000, CHINA.
³ Department of Radiation Oncology, First Affiliated Hospital of Gannan Medical University, Ganzhou, Ganzhou, 341000, CHINA.
⁴ School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, Guangzhou, 510000, CHINA.
⁵ Jiangxi Clinical Research Center for Cancer, Ganzhou, Ganzhou, 341000, CHINA.
⁶ First Clinical Medical College, Gannan Medical University, Ganzhou, Ganzhou, 341000, CHINA.
⁷ Mathematics and Computer Science, Gannan Normal University, Ganzhou, Ganzhou, 341000, CHINA.
⁸ Sun Yat-sen University Cancer Center, East Dongfeng Road 651, Guangzhou, Guangdong, China, Guangzhou, Guangdong, 510060, CHINA.

PMID: 38670137
DOI: 10.1088/1361-6560/ad4445

Abstract

The dose hotspot areas in hypofractionated whole-breast irradiation greatly increase the risk of acute skin toxicity because of the anatomical peculiarities of the breast. In this study, we presented several novel planning strategies that integrate multiple sub-planning target volumes (sub-PTVs), field secondary placement, and RapidPlan models for right-sided hypofractionated whole-breast irradiation. Methods: A total of 35 cases of whole-breast irradiation with a dose of 42.5Gy for PTVs using tangential intensity-modulated radiotherapy(IMRT) were selected. Both PTVs were planned for simultaneous treatment using the original manual multiple sub-PTV plan (OMMP) and the original manual single-PTV plan (OMSP). The manual field secondary placement multiple sub-PTV plan (m-FSMP) with multiple objects on the original PTV and the manual field secondary placement single-objective plan (m-FSSP) were initially planned, which were distribution-based of V105(volume receiving 105% of the prescription dose). In addition, two RapidPlan-based plans were developed, including the RapidPlan-based multiple sub-PTVs plan (r-FSMP) and the RapidPlan-based single-PTV plan (r-FSSP). Dosimetric parameters of the plans were compared, and V105 was evaluated using multivariate analysis to determine how it was related to the volume of PTV and the interval of lateral beam angles (ILBA).Results: The lowest mean V105 (5.64±6.5%) of PTV was observed in m-FSMP compared to other manual plans. Upon validation, r-FSSP demonstrated superior dosimetric quality for OAR compared to the two other manual planning methods, except for V5(the volume of ipsilateral lung receiving 5 Gy) of the ipsilateral lung. While r-FSMP showed no significant difference (p=0.06) compared to r-FSSP, it achieved the lowest V105 value (4.3±4.5%), albeit with a slight increase in the dose to some OARs.Conclusions: m-FSMP and r-FSMP can substantially enhance the homogeneity index (HI) and reduce V105, thereby minimizing the risk of acute skin toxicities, even though there may be a slight dose compromise for certain OARs.

Keywords: RapidPlan; field secondary placement; hypofractionated; sub-planning target volumes; whole-breast irradiation.