ESTRO 2024 - Abstract Book

S1745

Clinical - Lung

ESTRO 2024

toxicity in patients suffering from MPM that undergoing RHR and to explore its possible association with dosimetric parameters.

Material/Methods:

We analyzed, through a retrospective study, 117 patients affected by MPM who had performed RHR after chemotherapy and non-radical surgery. The radiotherapy treatment was delivered with Helical Tomotherapy technology with a fractionation scheme of 50 Gy in 25 fractions plus simultaneous boost on macroscopic residual disease (60 Gy in 25 fractions). The Planned Target Volume was delineated taking account of breathing excursions and included the entire thickness of the rib cage, the surgical scar, the visceral pleura with pericardium, the ipsilateral mediastinic lymph nodes and the diaphragm (up to L2). Oesophageal toxicity was recorded with the "Common Terminology Criteria for Adverse Events" (CTCAE Ed.4.0.) as follows: G0 toxicity: no collateral effects reported, G1 toxicity: symptomatic dysphagia but which did not interfere with regular diet, G2 toxicity: moderate pain, alteration in intake of food or swallowing, G3 toxicity: disabling pain, resulting in the need to proceed with enteral nutrition via PEG or parenteral nutrition. This assessment was made at the end of treatment (T0), at three months (T1) and after six months (T2). In each patient, in the contouring phase, the oesophagus was drawn in its entirety from the superior esophageal sphincter to the cardias. In planning phase of radiation treatment the volume (cc), V30(%), V50(%), D0.1(Gy), D98(Gy) Dmean(Gy) were evaluated.

For statistical analysis a non parametric approach was performed. In univariate analysis Mann-Whitney and Fisher exact test were performed, for multivariate analysis an ANOVA test was adopted.

Results:

From January 2010 to December 2018, 117 patients, 94 (80%) males and 23 (20%) females, were diagnosed with MPM and treated with a RHR scheme. The median age of the population was 68 years (33-83). Among these patients, 105 (89%) were affected by epithelioid MPM while 12 (11%) by biphasic or sarcomatoid MPM. The right lung was most commonly affected, with 69 (59%) cases compared to 48 (41%) cases in the left lung.. All patients