ESTRO 2022 - Abstract Book

S1106

Abstract book

ESTRO 2022

Purpose or Objective To evaluate feasibility, safety, and dosimetric results of volumetric modulated arc therapy (VMAT) to deliver hypofractionated radiotherapy (RT) in oesophageal cancer elderly patients, unfit for a multimodality curative strategy. Materials and Methods From June 2010 to October 2021, thirty-two patients were treated with hypofractionated VMAT for palliative/symptomatic setting. The prescription dose was 40 Gy in 16 fractions (EQD2 41.7 Gy considering an alfa/beta ratio of 10 Gy, and 44 Gy considering an alfa/beta ratio of 3 Gy).

Results

Eleven patients (31%) were symptomatic for grade 3 baseline dysphagia. RT was well tolerated; no patient interrupted the daily treatment. Acute toxicity was mild; no G3 acute toxicities were reported. At the end of treatment, 7 patients (22%) experienced a stable dysphagia and 22 (69%) an improvement of baseline dysphagia, while 3 patients (9%) reported a worsening of esophagitis. At a mean follow-up of 9 months, 18 patients (56%) had a complete clinical recovery (G0-1) of the symptomatic moderate/severe dysphagia. At 3 months after the end of RT, 9 patients (28%) achieved a partial or complete response. Two coplanar arcs were employed for VMAT delivery. Dosimetric results were consistent in term of both target coverage and normal tissue sparing. Conclusion Hypofractionated VMAT is an effective palliative treatment option in symptomatic advanced oesophageal cancer patients, non-suitable for a standard curative treatment.

Poster (digital): Lower GI

PO-1311 Rectal cancer with LPLN - T and node characteristics analysis: impact of SIB on oncological outcomes

E. Meldolesi 1 , R. Giannini 1 , G. Chiloiro 1 , B. Corvari 1 , S. Manfrida 1 , V. De Luca 1 , A. Romano 1 , N. Dinapoli 1 , V. Valentini 1 , M.A. Gambacorta 1

1 Fondazione Policlinico Universitario "A.Gemelli" - IRCS, Radioterapia, Roma, Italy

Purpose or Objective Involvement of lateral pelvic lymph node (LPLN) in patients with locally advanced rectal cancer (LARC) occurs between 7- 15% at the diagnosis, related to a worse prognosis with a 5-year survival rate between 30 to 40%. T and LPLN’s characteristics (e.g. location, size, RT dose) could carry essential information for the definition of the best treatment for this group of patients. The role of a simultaneous integrated radiotherapy boost on LPLN has been investigated. Materials and Methods We retrospectively collected data from LARC patients with LPLN at the primary staging MRI, treated in our center from March 2003 to December 2020. Patients underwent a neoadjuvant concomitant CTRT treatment on T, mesorectum and pelvic nodes, associated with a fluoride-based chemotherapy +/- oxaliplatin according with the primary stage. Patients were divided in two groups based on whether they received a simultaneous integrated RT boost on the LPLN or not. T and LPLN’s characteristics (e.g. location, size, RT dose) of our population have been investigated. Local control (LC), overall survival (OS), disease free survival (DFS) and metastasis free survival (MFS) were evaluated in the whole group and then compared between the two groups. Results A total of 176 patients were evaluated: 82 were included in the RT boost group and 94 in the non-RT boost group. The median follow-up period was 57.8 months (range 52.3 – 63.1). LC, OS, DFS and MFS resulted in 92%, 84.7%, 79.5% and 84.1%, respectively with a statistically significant difference, if considered the boost RT and no boost RT groups (p 0.026, 0.006, 0.042, 0.030) in favor of RT boost group. Initial location either T or LPLN, cranio-caudal T extension and LPLN size did not