Enhancing Radiotherapy for Locally Advanced Non-Small Cell Lung Cancer Patients with iCE, a Novel System for Automated Multi-Criterial Treatment Planning Including Beam Angle Optimization.

Kristine Fjellanger,Turid Husevåg Sulen,Inger Marie Sandvik,Ben J M Heijmen,Linda Rossi,Sebastiaan Breedveld,Helge Egil Seime Pettersen,Liv Bolstad Hysing

doi:10.3390/cancers13225683

Kristine Fjellanger, Turid Husevåg Sulen + Show 6 more

Open Access

https://doi.org/10.3390/cancers13225683

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Abstract

Simple SummaryIn treatment planning for intensity-modulated radiotherapy (IMRT), optimization objectives and beam angle settings are individualized for the anatomy of each patient. This is a complex interactive process that is usually performed by a treatment planner. In this study, a novel system for automated optimization of IMRT plans with integrated beam angle optimization (BAO) was developed, and used to systematically investigate the impact of selected beam angles on treatment plan quality for locally advanced non-small cell lung cancer (LA-NSCLC). Automatically generated plans were of a higher quality than the manually generated, clinically delivered plans, while dramatically reducing the planning workload. The study demonstrates the potential for automated planning with integrated BAO to enhance radiotherapy for LA-NSCLC patients.In this study, the novel iCE radiotherapy treatment planning system (TPS) for automated multi-criterial planning with integrated beam angle optimization (BAO) was developed, and applied to optimize organ at risk (OAR) sparing and systematically investigate the impact of beam angles on radiotherapy dose in locally advanced non-small cell lung cancer (LA-NSCLC). iCE consists of an in-house, sophisticated multi-criterial optimizer with integrated BAO, coupled to a broadly used commercial TPS. The in-house optimizer performs fluence map optimization to automatically generate an intensity-modulated radiotherapy (IMRT) plan with optimal beam angles for each patient. The obtained angles and dose-volume histograms are then used to automatically generate the final deliverable plan with the commercial TPS. For the majority of 26 LA-NSCLC patients, iCE achieved improved heart and esophagus sparing compared to the manually created clinical plans, with significant reductions in the median heart Dmean (8.1 vs. 9.0 Gy, p = 0.02) and esophagus Dmean (18.5 vs. 20.3 Gy, p = 0.02), and reductions of up to 6.7 Gy and 5.8 Gy for individual patients. iCE was superior to automated planning using manually selected beam angles. Differences in the OAR doses of iCE plans with 6 beams compared to 4 and 8 beams were statistically significant overall, but highly patient-specific. In conclusion, automated planning with integrated BAO can further enhance and individualize radiotherapy for LA-NSCLC.

Highlights

The standard treatment for locally advanced non-small cell lung cancer (LA-NSCLC) is concurrent chemoradiotherapy [1]
The results showed that plans with optimized beam angles had similar quality to clinical plans with manually selected beam angles
Treatment plans were created on the average intensity projection (AIP) of the 4DCT and treatment was given in free breathing (FB) conditions as a standard

Summary

Introduction

The standard treatment for locally advanced non-small cell lung cancer (LA-NSCLC) is concurrent chemoradiotherapy [1]. Intensity-modulated radiotherapy (IMRT) is the state-of-the-art radiation technique, allowing optimal shaping of the delivered dose to the target. The aim of radiotherapy treatment planning is to establish treatment unit settings for each patient that will result in a high-quality dose distribution, i.e., a high dose inside the target volume and limited dose outside, especially in the OARs. IMRT treatment plans are generated using a cost function that defines the planning objectives for the target, OARs and other tissues, and their relative weights. In manual IMRT treatment planning, the general approach is to begin the plan generation for a new patient using a tumor-site-specific template for the cost function. For fixed-beam IMRT treatment in the thorax, the beam angles should be individually tuned, as IMRT with carefully selected beam angles can reduce OAR doses compared to volumetric modulated arc therapy (VMAT) or IMRT with nonoptimized beam angles [4]. A number of studies have demonstrated that manually created plans may be suboptimal [5,6,7,8,9]

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