Automated Hypofractionated IMRT treatment planning for early-stage breast Cancer

Abstract

Background: Hypofractionated whole-breast irradiation is a standard adjuvant therapy for early-stage breast cancer. This study evaluates the plan quality and efficacy of an in-house-developed automated radiotherapy treatment planning algorithm for hypofractionated whole-breast radiotherapy. Methods: A cohort of 99 node-negative left-sided breast cancer patients completed hypofractionated whole-breast irradiation with six-field IMRT for 42.56 Gy in 16 daily fractions from year 2016 to 2018 at a tertiary center were replanned with an in-house-developed algorithm. The automated plan-generating C#-based program is developed in a Varian ESAPI research mode. The dose-volume histogram (DVH) and other dosimetric parameters of the automated and manual plans were directly compared. Results: The average time for generating an autoplan was 5 to 6 min, while the manual planning time ranged from 1 to 1.5 h. There was only a small difference in both the gantry angles and the collimator angles between the autoplans and the manual plans (ranging from 2.2 to 5.3 degrees). Autoplans and manual plans performed similarly well in hotspot volume and PTV coverage, with the autoplans performing slightly better in the ipsilateral-lungsparing dose parameters but were inferior in contralateral-breast-sparing. The autoplan dosimetric quality did not vary with different breast sizes, but for manual plans, there was worse ipsilateral-lung-sparing (V 4Gy ) in larger or medium-sized breasts than in smaller breasts. Autoplans were generally superior than manual plans in CI (1.24 ± 0.06 vs. 1.30 ± 0.09, p < 0.01) and MU (1010 ± 46 vs. 1205 ± 187, p < 0.01). Conclusions:Our study presents a well-designed standardized fully automated planning algorithm for optimized whole-breast radiotherapy treatment plan generation. A large cohort of 99 patients were re-planned and retrospectively analyzed. The automated plans demonstrated similar or even better dosimetric quality and efficacy in comparison with the manual plans. Our result suggested that the autoplanning algorithm has great clinical applicability potential.

Assessing the performance of an automated breast treatment planning software

“…Each iteration proceeds in a trial‐and‐error fashion, with the planner editing the fluence, calculating 3D dose, and evaluating the dose until “optimal” dosimetry is achieved. There are several published studies on automated treatment planning algorithms being implemented for various anatomical sites, including breast 8–16 . Many institutions use in‐house developed software for plan automation, and while that is a feasible solution for those that already have it or have the resources to develop, maintain,and validate in‐house solutions, such an approach may not be accessible for many nonacademic clinics.…”

“…There are several published studies on automated treatment planning algorithms being implemented for various anatomical sites, including breast. [8][9][10][11][12][13][14][15][16] Many institutions use in-house developed software for plan automation, and while that is a feasible solution for those that already have it or have the resources to develop, maintain,and validate in-house solutions, such an approach may not be accessible for many nonacademic clinics. Commercially available software such as EZF, therefore can provide an ideal solution for those that have limited time and resources.…”

Clinical Experience With Machine Learning-Based Automated Treatment Planning for Whole Breast Radiation Therapy

“…There have been excellent studies to develop automated tools for breast treatment planning processes with the goals of improving planning efficiency and standardizing plan quality. 18 , 19 , 20 , 21 , 22 , 23 Those tools were developed to automate 3D CRT, 18 field-in-field, 19 , 23 or intensity modulated radiation therapy techniques. 21 , 22 Our auto-planning tool was developed based on the irregular surface compensator technique because our institution has been using it for over 15 years.…”

Auxiliary Structures-Assisted Radiotherapy Improvement for Advanced Left Breast Cancer

“…For example, rings around the target, with different thicknesses and locations, were used to restrict the dose distribution for the target and intermediate-high dose for the ipsilateral lung (22). Xu et al used a blocking structure to block low doses in the lungs (23), while Lin et al demonstrated the use of conformed rings as dose constraint structures for whole-breast radiotherapy planning (24). The two different rings can separately restrict the unwanted intermediate-high dose for the ipsilateral lungs and heart, and the low dose for the contralateral lung.…”

“…used a blocking structure to block low doses in the lungs ( 23 ), while Lin et al. demonstrated the use of conformed rings as dose constraint structures for whole-breast radiotherapy planning ( 24 ). The two different rings can separately restrict the unwanted intermediate-high dose for the ipsilateral lungs and heart, and the low dose for the contralateral lung.…”