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A Multi-Institutional Study Investigating the Performance of a Knowledge-Based Planning System Against Pinnacle Auto-Planning Engine in SIB-IMRT for the Head-And-Neck Cancer

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B Wu

B Wu1*, M Kusters2 , M Kunze-busch2 , T Dijkema2 , T McNutt3 , G Sanguineti4 , D Pang1 , (1) Georgetown University Hospital, Washington,DC (2) Radboud University Medical Center, Nijmegen, Netherlands (3) Johns Hopkins University, Baltimore, MD (4) Istituto Nazionale Tumori Regina Elena, Roma, Italy


MO-G-201-1 (Monday, August 1, 2016) 5:15 PM - 6:00 PM Room: 201

Purpose: Knowledge-based Planning (KBP) founded on prior planning experience and Auto-Planning Engine (APE; commercialized in Pinnacle v9.10 TPS) based on progressive optimization algorithm both aim to eliminate the trial-and-error process in radiotherapy inverse planning. This study investigates the performance of the approaches in a multi-institutional setting to evaluate their functionalities in oropharyngeal cancer and offers suggestions how they can be implemented in the clinic.

Methods: Radboud University Medical Center (RUMC) provided 35 oropharyngeal cancer patients (SIB-IMRT with two-dose-level prescription: 68 Gy to PTV68 and 50.3 Gy to PTV50.3) with corresponding comparative APE plans. Johns Hopkins University (JHU) contributed to a three-dose-level (70 Gy, 63 Gy and 58.1 Gy) plan library for RUMC’s patient KBP generation. MedStar Georgetown University Hospital (MGUH) contributed to a KBP approach employing overlap-volume histogram (OVH-KBP) for generating RUMC’s patient KBP plans using JHU’s plan library. Since both approaches need their own user-defined parameters as initial inputs, the first 10 patients were set aside as training set to finalize them. Meanwhile, cross-institutional comparisons and adjustments were implemented for investigating institutions’ protocol discrepancies, and the approaches’ user-defined parameters were updated accordingly. The finalized parameters were then applied to the remaining 25 patients for OVH-KBP and APE generation. A Wilcoxon rank-sum test was used for statistical comparison with significance level of p<0.05.

Results: On average, PTV68’s V95 was 96.5% in APE plans vs. 97% in OVH-KBP plans (p=0.36); PTV50.3’s V95 in APE plans was 97.8% vs.97.6% in OVH-KBP plans (p=0.6); cord’s D0.1 cc was 38.6 Gy in OVH-KBP plans vs. 43.7 Gy in APE plans (p=0.0001); mean doses to larynxes, oral cavities, parotids and submandibular glands were similar with p>0.2.

Conclusions: The study demonstrates that KBP and APE can generate plans of comparable quality in a multi-institutional setting. Variations in clinical protocols can be effectively addressed for cross-institutional adaptations.

Funding Support, Disclosures, and Conflict of Interest: Binbin Wu and Todd McNutt are the co-inventors of a patent associated with the proposed knowledge-based planning system, which was licensed to Varian Medical Systems in 2015; This research was in part supported by Philips Radiation Oncology Systems.

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