ESTRO 2023 - Abstract Book

S1101

Digital Posters

ESTRO 2023

All submitted volumes were found to be either acceptable as per protocol or acceptable with variation for entry into the SCOPE2 trial. Errors related to editing of clinical target volumes for OARs and CTVA length unrelated to protocol accounted for some of the differences observed in the submitted volumes. In one case, the ITV volume was consistently smaller as a result of following the updated guidance, due to extremes of the respiratory cycle not being adequately covered (Figure 1).

Calculated values of the mean JCI and GMI for each case, as summarised in Table 1, show good agreement between the target volumes produced by following both the original and streamlined outlining methods. Conclusion The streamlined 4D outlining methodology produced clinically acceptable target volumes, which agreed well with the existing 3-phase delineation methodology published in the SCOPE2 RGPD. This shows that the streamlined methodology maintains robustness in target volume delineation while reducing the demands on clinicians’ time. The issues observed for one case B submission, where the extremes of breathing motion were not fully-accounted for, resulting in a consistently smaller ITV (Figure 1) highlights the need for careful review of the ITV on all breathing phases.

The streamlined process will be introduced into the SCOPE2 RPGD as an amendment, offering an alternative for trial centres wishing to treat using 4DCT within the trial. Timely-retrospective reviews will be carried out for the first cases for centres switching to the new method to guarantee the suitability of the target volumes.

PO-1372 Stereotactic Radiotherapy In Pancreatic Cancer: An Update Of A National Survey

M. Lucarelli 1 , C. Di Carlo 2 , G. Mantello 2 , M.F. Osti 3 , A. Guido 4 , S. Montrone 5 , A. Bacigalupo 6 , A. Ciabattoni 7 , B. Meduri 8 , G. Macchia 9 , F. Cellini 10 , L. Giaccherini 11 , M. Lupatelli 12 , M. Bignardi 13 , M. Fiore 14 , M. Troiano 15 , N. Simoni 16 , R. Mazzarotto 17 , M. Loi 18 , R.M. Niespolo 19 , V. Borzillo 20 , M.A. Gerardi 21 , T. Comito 22 , L. Caravatta 1 1 SS. Annunziata Hospital, Department of Radiation Oncology, Chieti, Italy; 2 Azienda Ospedaliero Universitaria Ospedali Riuniti, Radiation therapy Unit, Ancona, Italy; 3 Sant'Andrea Hospital, Sapienza University, Unit of Radiation Oncology, Roma, Italy; 4 IRCCS Azienda Ospedaliero-Universitaria, Radiation Oncology, Bologna, Italy; 5 Pisa University Hospital, Radiation Oncology Unit, Pisa, Italy; 6 IRCCS Ospedale Policlinico San Martino, Department of Radiation Oncology, Genova, Italy; 7 San Filippo Neri Hospital, U.O.C. Radioterapia, Roma, Italy; 8 University Hospital of Modena, Radiation Oncology Unit, Modena, Italy; 9 Gemelli Molise Hospital-Universita' Cattolica del Sacro Cuore, Radiation Oncology Unit, Campobasso, Italy; 10 Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Radioterapia Oncologica ed Ematologia, Dipartimento di Diagnostica per Immagini, Roma, Italy; 11 Azienda USL-IRCCS, Radiation Therapy Unit, Reggio Emilia, Italy; 12 University of Perugia and Perugia General Hospital, Radiation Oncology Section, Perugia, Italy; 13 Fondazione Poliambulanza, Radiation Oncology Centre, Brescia, Italy; 14 Campus Bio-Medico University Hospital Foundation, Radiation Oncology, Roma, Italy; 15 Fondazione "Casa Sollievo Della Sofferenza" IRCCS, San Giovanni Rotondo, S.S.D. Fisica Sanitaria, Foggia, Italy; 16 Azienda Ospedaliera Universitaria, Radiotherapy Unit, Parma, Italy; 17 Azienda Ospedaliero Universitaria Integrata, Department of Radiation Oncology, Verona, Italy; 18 Azienda Ospedaliero Universitaria Careggi, Radiation Oncology Unit - Oncology Department, Firenze, Italy; 19 Azienda Ospedaliera San Gerardo , Radiotherapy Unit, Monza, Italy; 20 Istituto Nazionale Tumori IRCCS Fondazione Pascale , Division of Radiotherapy, Napoli, Italy; 21 IEO European Institute of Oncology, IRCCS, Department of Radiotherapy, Milano, Italy; 22 Humanitas Clinical and Research Hospital IRCCS, , Radiotherapy Department, Rozzano, Italy Purpose or Objective Stereotactic body radiation therapy (SBRT) has significantly changed the management of pancreatic cancer, with the advantages of a short overall treatment time and potentially ablative doses. Since a great variability about indications and doses were reported before ASTRO guidelines publication, in October 2018 the AIRO study group of gastrointestinal malignancies proposed a national survey aiming to investigate this scenery. Currently, a new treatment paradigm is emerging, with a gradual transition from standard to ablative dose radiotherapy. Aiming to assess how the Italian centers have adapted their clinical practice to these changes, an update of the survey has been carried out.

Materials and Methods