ESTRO 2022 - Abstract Book

S923

Abstract book

ESTRO 2022

PO-1087 Tumour volume response to induction chemotherapy in nasopharyngeal carcinoma: TPF versus GP

O. Nouri 1 , W. Mnejja 1 , N. Fourati 1 , F. Dhouib 1 , W. Siala 1 , I. Charfeddine 2 , A. Khanfir 3 , L. Farhat 1 , J. Daoud 1

1 Habib Bourguiba University Hospital, Department of Oncology Radiotherapy, Sfax, Tunisia; 2 Habib Bourguiba University Hospital, Department of Oto-Rhino-Laryngology, Sfax, Tunisia; 3 Habib Bourguiba University Hospital, Department of Medical Oncology, Sfax, Tunisia Purpose or Objective Adding induction chemotherapy (IC) to concomitant chemo radiotherapy (CCR) is the new standard of care for locally advanced nasopharyngeal carcinoma (NPC). Taxanes-cisplatin-5 fluoro-uracil (TPF) and gemcitabine-cisplatin (GP) regimens proved through randomized trials that they improve metastatic free and overall survival. To date, response to IC of these two regimens has not been compared. The aim of this single institute study was to evaluate and compare tumour volume response to both regimens. Materials and Methods We retrospectively reviewed the data of patients with locally advanced stage III-IV NPC treated between 2017 and 2021. All patients received three IC courses (TPF or GP) followed by CCR with intensity-modulated radiotherapy (IMRT) and weekly cisplatin (40 mg/m ² ). Patients who received GP IC were compared to 3 TNM-stage-correlated patients treated with TPF IC. IMRT was delivered with integrated simultaneous boost of 33 daily fractions at a total dose of 69.96 Gy. For each patient, two dosimetric-computed tomography (CT) were made: one before the beginning of IC and the second one week after the completion of IC. We delineated tumour volume (GTV T), lymph node volume (GTV N) and total volume (GTV) on both CTs. We compared volumes responses to each regimen. Results Forty patients were included: ten received GP and thirty received TPF IC. Mean age was 47 and sex ratio was 1.9. Thirty- six patients (90%) had an UCNT. In the two regimens, half of the patients (50%) were classified as stage III and the other half as stage IV. The mean GTV T before IC was 50.4 cm ³ [17-221.5]. After IC, there was a decrease in GTV T with an average of 32.3% in GP regimen versus 41% in TPF regimen. The GTV N before IC was 62.9 cm ³ on average [3.7-250.7]. The mean regression of its volume was of 48.2% versus 57.1% in GP and TPF regimens respectively. The average total GTV before IC was 113.4 cm ³ [28.1-295.9]. The mean decrease in total GTV was 39.5% with GP versus 49.9% with TPF. Conclusion IC allowed reduction of macroscopic tumour and lymph node volumes with both regimens. However, TPF regimen appears to provide a better tumour response than GP. We must validate these results with more patients, longer follow up and correlate this observation with NPCs survival outcomes and toxicity profiles. D. Alrerio 1 , G. Corrao 2 , S. Zorzi 3 , G. Agostini 4 , G. Marvaso 2 , S. Volpe 2 , L. Bergamaschi 2 , C. Pedone 2 , J. Franzetti 2 , C. Bonfiglio 2 , A.M. Camarda 2 , M. Tagliabue 5 , M. Cossu Rocca 6 , M. Ansarin 3 , B.A. Jereczek-Fossa 2 1 IEO, European Institute of Oncology IRCCS, Division of Radiation Oncology, Milan, Italy; 2 IEO, European Institute of Oncology IRCCS; University of Milan, Division of Radiation Oncology; Department of Oncology and Hematoncology, Milan, Italy; 3 IEO, European Institute of Oncology IRCCS, Division of Otolaryngology and Head and Neck Surgery, Milan, Italy; 4 University of Perugia, Section of Otolaryngology-Head and Neck Surgery, Milan, Italy; 5 IEO, European Institute of Oncology IRCCS; University of Sassari, Division of Otolaryngology and Head and Neck Surgery; Department of Biomedical Sciences, Milan, Italy; 6 IEO, European Institute of Oncology IRCCS, Department of Medical Oncology, Urogenital and Head and Neck Tumors Medical Treatment, Milan, Italy Purpose or Objective Locally advanced oropharyngeal cancers (LAOPCs) can be treated with both non-surgical (chemoradiation) and surgical approaches. Whether the use of modern techniques (Intensity Modulated Radiotherapy -IMRT- and Transoral Robotic Surgery - TORS) could impact the toxicity profile of these two strategies has not been well established yet. Aim of the present study was to compare acute and long-term treatment-related side effects of two cohorts of patients (pts) with LAOPC treated with curative IMRT or TORS followed by postoperative IMRT. Materials and Methods We retrospectively reviewed pts treated at our Institute from 2015 to 2020 for LAOPC. Inclusion criteria were: 1) locally advanced stages (III and IV according to AJCC 7 th Ed) 2) treated with IMRT (+/- chemotherapy - CT) or TORS followed by postoperative radiotherapy (PORT). Exclusion criteria were: 1) recurrent tumors 2) previous treatments on the head and neck region 4) 3D conformal radiotherapy technique 3) palliative treatments. Acute (at the end of the IMRT course) and early-late (at one year from the end of IMRT course) toxicities were reported according to Common Terminology Criteria Adverse Events (CTCAE v.3.04). Enteral nutrition, tracheostomia and oesophageal stricture occurred at any time during the follow-up period were also reported. PO-1088 Toxicity Profile Of 100 Oropharyngeal Cancer Patients Treated With Modern Approaches

Results