Comparison of dose metrics between automated and manual radiotherapy planning for advanced stage non-small cell lung cancer with volumetric modulated arc therapy.

Abstract

Advanced stage non-small cell lung cancer (AS-NSCLC) is generally treated with concurrent chemoradiotherapy using a radiation dose of 60–66 Gray (Gy) in 30–33 fractions over six-seven weeks [1]. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) are widely used treatment techniques [2]. Radiation treatment plans are becoming increasingly complex [3] and manual optimization of treatment plans is time-consuming and the quality of the plan is operator dependent [4]. The increasing complexity of treatment plans complicates the optimization procedure and thereby augments the rate of inconsistency between manually derived treatment plans [3], [5]. Several trial-and-error optimization processes are usually required to achieve clinically acceptable plans. More manual actions could influence consistency and plan quality of the manual treatment plans [3], [4]. The experience of the planner has a large impact on plan quality and dissemination of best practices could help improve these variations [6]. Aforementioned drawbacks of manual treatment planning might be overcome by automating treatment planning. Most treatment planning systems currently have integrated an automated treatment planning solution. In addition, there are also in-house developed automated treatment planning systems [7]. Automated treatment planning methods are aimed to reduce the inter-planner variability and the planning time during the optimization process and to improve plan quality. Different sites investigated were already investigated such as head and neck (H&N) [4], [5], [8], [9], prostate [10] and oesophagus [11]. Automated treatment plans for AS-NSCLC radiation therapy are not much represented yet. The location of a tumor in the lung varies more than the location of a tumor in the H&N area or the prostate. This variability may cause a difference in the result of automated treatment planning techniques. Della Gala et al. [7] investigated different radiation techniques for AS-NSCLC by comparing originally manually planned IMRT treatment plans versus automated VMAT treatment plans with their in-house developed treatment planning system Erasmus-iCycle. In this study we have investigated, if automated treatment planning is able to create treatment plans with consistent quality using a single optimization preset including beam set-up, dose prescription, objectives and priorities for organs at risk (OARs), and planning target volumes (PTVs) for AS-NSCLC. A comparison is presented between automated and manually generated VMAT treatment plans for AS-NSCLC.