Multicriteria optimization enables less experienced planners to efficiently produce high quality treatment plans in head and neck cancer radiotherapy.

Roel GJ Kierkels,Roel JHM Steenbakkers,Aart A van ‘t Veld,Erik W Korevaar,Hendrik P Bijl,Johannes A Langendijk,Ruurd Visser

doi:10.1186/s13014-015-0385-9

Abstract

ObjectivesTo demonstrate that novice dosimetry planners efficiently create clinically acceptable IMRT plans for head and neck cancer (HNC) patients using a commercially available multicriteria optimization (MCO) system.MethodsTwenty HNC patients were enrolled in this in-silico comparative planning study. Per patient, novice planners with less experience in dosimetry planning created an IMRT plan using an MCO system (RayStation). Furthermore, a conventionally planned clinical IMRT plan was available (Pinnacle3). All conventional IMRT and MCO-plans were blind-rated by two expert radiation-oncologists in HNC, using a 5-point scale (1–5 with 5 the highest score) assessment form comprising 10 questions. Additionally, plan quality was reported in terms of planning time, dosimetric and normal tissue complication probability (NTCP) comparisons. Inter-rater reliability was derived using the intra-class correlation coefficient (ICC).ResultsIn total, the radiation-oncologists rated 800 items on plan quality. The overall plan score indicated no differences between both planning techniques (conventional IMRT: 3.8 ± 1.2 vs. MCO: 3.6 ± 1.1, p = 0.29). The inter-rater reliability of all ratings was 0.65 (95% CI: 0.57–0.71), indicating substantial agreement between the radiation-oncologists. In 93% of cases, the scoring difference of the conventional IMRT and MCO-plans was one point or less. Furthermore, MCO-plans led to slightly higher dose uniformity in the therapeutic planning target volume, to a lower integral body dose (13.9 ± 4.5 Gy vs. 12.9 ± 4.0 Gy, p < 0.001), and to reduced dose to the contra-lateral parotid gland (28.1 ± 11.8 Gy vs. 23.0 ± 11.2 Gy, p < 0.002). Consequently, NTCP estimates for xerostomia reduced by 8.4 ± 7.4% (p < 0.003). The hands-on time of the conventional IMRT planning was approximately 205 min. The time to create an MCO-plan was on average 43 ± 12 min.ConclusionsMCO planning enables novice treatment planners to create high quality IMRT plans for HNC patients. Plans were created with vastly reduced planning times, requiring less resources and a short learning curve.

Highlights

For patients with head and neck cancer (HNC), intensitymodulated radiotherapy (IMRT) has been demonstrated to reduce radiation induced complications, as compared to conventional radiation delivery techniques [1,2]
IMRT allows for dose distributions with curative intended dose to tumor tissue, with an attempt to minimize dose to organs at risk (OARs) related to late toxicities, such as xerostomia and dysphagia [3,4]
Prescriptions and delineation The study cohort consisted of twenty patients, of which 11 males and 9 females, diagnosed with stage II-IV squamous cell carcinoma of the head and neck, which were successively selected from a database of HNC patients included in a prospective standard follow up program

Summary

Introduction

For patients with head and neck cancer (HNC), intensitymodulated radiotherapy (IMRT) has been demonstrated to reduce radiation induced complications, as compared to conventional radiation delivery techniques [1,2]. The trade-offs between the target(s) and the relative large number of OARs in the head and neck area cause the conventional treatment planning procedure to be cumbersome. The creation of a conventional IMRT plan requires an iteration loop of changing patient specific trade-off objectives and dose re-computations, and is subjective. Conventional IMRT increases the planning time and contains a relatively long learning curve [5,6,7]. The increasing demand of IMRT and VMAT plans, requires efficient departmental workflows

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