ESTRO 2024 - Abstract Book

S1768

Clinical - Lung

ESTRO 2024

Results:

The median GTV was 38 cc (range: 2.4-84.0 cc), corresponding to a tumor diameter of 4.2 cm (range: 1.7-5.4 cm). Most of the plans satisfied the lung V20 constraint, with minimal deviations in one CIRT plan and seven photon SABR plans. When stratified by tumor size, CIRT demonstrated a significantly lower MLD (CIRT: 3.0% ± 0.5 vs photon SABR: 4.6% ± 1.3, p=0.002), V20 (CIRT: 6.4% ± 1.4 vs photon SABR: 9.0 ± 3.1 p=0.004) and lower incidence of RP than photon SABR for tumors larger than 4 cm (CIRT: 3.0% ± 0.5 vs photon SABR: 4.6% ± 1.3, p=0.002)). Conversely, for tumors smaller than 4 cm, there was no significant difference in MLD (CIRT: 2.94Gy ± 1.08 vs photon SABR: 3.36Gy± 1.47, p=0.097),

, V20 (CIRT: 5.3% ± 2.3 vs photon SABR: 4.8 ± 3.3 p=0.312), and the incidence of RT pneumonitis between two modalities (CIRT: 2.6% ± 0.6 vs photon SABR: 3.0% ± 1.4, p=0.171).

Conclusion:

Based on our in-silico study, CIRT could significantly spare lung dose and reduce the risk of RP for tumors with a diameter greater than 4cm. Although this finding requires clinical validation, it holds significant value for future clinical research design and treatment planning.

Keywords: CIRT, Lung SABR, RT pneumonitis

2679

Digital Poster

ROLE OF STEREOTACTIC RADIOTHERAPY IN OLIGO-RECURRENCE OF PLEURAL MESOTHELIOMA

Alberto Revelant 1 , Francesca Gessoni 2 , Loredana Barresi 3 , Annalisa Drigo 3 , Giovanni Pirrone 3 , Jerry Polesel 4 , Lorenzo Vinante 1 , Angela Caroli 1 , Federica Bertini 1 , Anna Gorza 1 , Giuseppe Fanetti 1 , Federico Navarria 1 , Elisa Palazzari 1 , Fabio Matrone 1 , Alessandra Donofrio 1 , Maurizio Mascarin 1 1 CRO-IRCCS, Radiotherapy, Aviano, Italy. 2 Università degli studi di Padova, Radiotherapy, Padova, Italy. 3 CRO-IRCCS, medical physics, Aviano, Italy. 4 CRO-IRCCS, Cancer Epidemiology, Aviano, Italy

Purpose/Objective:

Malignant Pleural Mesothelioma (MPM) is an aggressive neoplasm with limited second-line therapeutic possibilities. The objective of our study is to evaluate the possible clinical impact of reirradiation with Stereotactic Ablative Body Radiation Therapy (SABR) in the setting of oligo-recurrent MPM after systemic, surgical and radiotherapy treatment with radical intent.