ESTRO 2022 - Abstract Book

S104

Abstract book

ESTRO 2022

OC-0127 Validation of lexicographic optimisation-based planning for locally advanced cervical cancer

S. Trivellato 1 , P. Caricato 1,2 , R. Pellegrini 3 , G. Montanari 1 , V. Faccenda 1,2 , S. Meregalli 4 , E. Bonetto 4 , S. Arcangeli 4,5 , E. De Ponti 1,5 1 ASST Monza, Medical Physics Department, Monza, Italy; 2 University of Milan, Department of Physics, Milan, Italy; 3 Elekta AB, Global Clinical Science, Stockholm, Sweden; 4 ASST Monza, Department of Radiation Oncology, Monza, Italy; 5 University of Milan Bicocca, School of Medicine and Surgery, Milan, Italy Purpose or Objective Recent advances in automated treatment planning demonstrated improved plan quality and best practice reducing routine planning workload. In this study, a not yet commercially available fully-automated lexicographic optimisation (LO) planning, called mCycle (Elekta AB, Stockholm), has been validated for locally advanced cervical cancer. Materials and Methods Twenty cervical cancer treatment plans (50 Gy in 25 fx) delivered between November 2019 and July 2021 have been retrospectively selected and re-planned by mCycle (Monaco 5.59.13). Constraints and objectives were sequentially optimized by multi-criterial optimization (MCO) according to an a-priori assigned priority list, a so-called Wish List (WL). Four patient sets have been used to achieve a robust WL. Main criteria for planning approval were a target coverage V 95% > 97% (acceptable > 95%), target D 1% < 105%, a bowel volume receiving more than 45 Gy less than 195 cm 3 (V 45 Gy < 195 cm 3 ), rectum and bladder spared as much as possible. Manual plan (MP) and mCycle plans (mCP) were compared in terms of dose- volume constraints and plan complexity, i.e. MUs and modulation degree (MD), performing the Wilcoxon Mann Whitney test to assess statistical significance ( α =0.05). Plan deliverability was verified by treatment QA. Results The re-planning of 20 plans took 3 working days. Plan comparison showed an increased target dose coverage passing from a V 95% of (97.1 ± 1.2)% for MP to (98.1 ± 2.5)% for mCP (p = 0.002). The median bowel V 45Gy , rectum and bladder mean doses were 183.2 cm 3 , 39.4 Gy, and 40.7 Gy for MP and 189.7 cm 3 , 38.0 Gy, and 38.8 Gy for mCP, respectively (p > 0.05). The average modulation degree was 3.1 ± 0.4 and 3.3 ± 0.3 for MP and for mCP, respectively (p > 0.05). The average MUs were increased, registering 733.5 ± 84.0 and 797.3 ± 65.6 for MP and mCP, respectively (p = 0.02) but registering a comparable gamma analysis (local 3%/3mm). Conclusion The novel mCycle autoplanning produced high-quality clinically acceptable plans significantly reducing the overall planning time: at our Institution, medical physicists are typically given one day to optimize one cervical cancer treatment. While the OAR sparing was comparable between MP and mCP, the target coverage was significantly increased. Despite the higher MU number, the plan deliverability has been preserved. The validation showed the mCycle capability to generate high- quality deliverable plans according to institutional-specific planning protocols. C. Fiandra 1 , S. Zara 2 , A. Alparone 2 , G. Loi 3 , A. Roggio 4 , A. Ciarmatori 5 , I. Benvenuto 6 , A. Poggiu 7 , A. Di Dio 8 , E. Verdolino 9 , F. Rosica 10 , S. Ren Kaiser 11 , L. Strigari 12 , L. Reversi 13 , E. Pierpaoli 14 , P. Ferrari 15 , L. Placidi 16 , S. Comi 17 , E. Infusino 18 , M. Coeli 19 , E. Gino 20 , T. Licciardello 21 , N. Romeo 22 , N. Ciscognetti 23 , G.M. Deotto 24 , S. Cora 25 , S. Pesente 26 , L. Rossi 27 , U. Ricardi 1 , B. Heijmen 28 , M. Marrocco 29 1 University of Torino, Department of Oncology, Turin, Italy; 2 Tecnologie Avanzate, Research and Development, Turin, Italy; 3 'Maggiore della Carità’ University Hospital, Medical Physics, Novara, Italy; 4 Veneto Institute of Oncology IOV-IRCCS, Medical Physics, Padova, Italy; 5 AORMN, Medical Physics, Pesaro, Italy; 6 IRCCS-CROB, Radiotherapy, Rionero in Vulture, Italy; 7 AOU, Fisica Sanitaria, Sassari, Italy; 8 Città della Salute e della Scienza, Medical Physics, Turin, Italy; 9 Ospedale S. G. MOSCATI, Medical Physics, Taranto, Italy; 10 ASL Teramo, Medical Physics, Teramo, Italy; 11 Azienda Sanitaria Universitaria Giuliano Isontina, Fisica Sanitaria, Trieste, Italy; 12 IRCCS Azienda Ospedaliero-Universitaria di Bologna, Medical Physics, Bologna, Italy; 13 Ospedali Riuniti di Ancona, Medical Physics, Ancona, Italy; 14 Area Vasta 5 Asur P.O. Mazzoni, Medical Physics, Ascoli, Italy; 15 Azienda Sanitaria dell'Alto Adige, Medical Physics, Bolzano, Italy; 16 Fondazione Policlinico Universitario A. Gemelli IRCCS, Medical Physics, Rome, Italy; 17 European Institute of Oncology IRCCS, Medical Physics, Milan, Italy; 18 IFO Istituti Fisioterapici Ospitalieri, Medical Physics, Rome, Italy; 19 Azienda ULSS 9 Scaligera del Veneto, Medical Physics, Legnago, Italy; 20 AO Ordine Mauriziano di Torino, Fisica Sanitaria, Turin, Italy; 21 IRCCS Istituto Romagnolo per lo Studio dei Tumori, Medical Physics, Meldola, Italy; 22 S. Vincenzo Hospital, Medical Physics, Taormina, Italy; 23 ASL2 Savonese, Medical Physics, Savona, Italy; 24 University Hospital of Siena, Medical Physics, Siena, Italy; 25 San Bortolo Hospital, Medical Physics, Vicenza, Italy; 26 Tecnologie Avanzate, Research and Development, Udine, Italy; 27 Erasmus MC Cancer Institute, Medical Physics, Rotterdam, The Netherlands; 28 Erasmus MC Cancer centre, Radiation Oncology, Rotterdam, The Netherlands; 29 Campus Biomedico University, Radiation Oncology, Rome, Italy Purpose or Objective Investigate whether autoplanning could replace current clinical planning in Italy for whole breast irradiation after breast- sparing surgery, with/without boost, and with/without inclusion of regional lymph nodes. OC-0128 multi-institutional real-world validation of autoplanning for breast cancer

Materials and Methods