S854
Clinical - Lung
ESTRO 2026
Digital Poster 5113
(97%), women (65%), with adenocarcinoma in 53%. Median TILs was 5% (range 1-60), with high TILs observed in 32%. High-TILs was significantly associated with favorable OS, with a mOS of 63.5 mo. in high-TILs vs 30 mo. in the low-TILs (p=0.02). No differences were observed in PFS (p=0.17).Figure 1: Association between % TILs and OS in the NeoCT patient group
Feasibility of radical reirradiation of lung tumors in patients with previous breast radiotherapy Cæcilie G Ottosen 1,2 , Mai-Britt Linaa 1 , Jakob A Thomsen 3 , Birgitte V Offersen 1 , Ane Appelt 4 , Stine O Fredslund 1 , Marianne M Knap 1 , Lone Hoffmann 1 1 Department of Oncology, Aarhus University Hospital, Aarhus, Denmark. 2 Department of clinical medicine, Aarhus University, Aarhus, Denmark. 3 Department of pulmonology, Aarhus University Hospital, Aarhus, Denmark. 4 Department of Oncology, Rigshospitalet, Copenhagen, Denmark Purpose/Objective: High-dose reirradiation of pulmonary tumors in patients who have previously received postoperative radiotherapy for breast cancer is a relatively common but challenging clinical scenario. Reirradiation is a valuable treatment option for these patients, but knowledge on adverse events is limited. We report on severe adverse events, cumulative RT doses, and overall survival (OS) in patients treated with curative reirradiation to the lungs after previous postoperative
Figure 2: Association between % TILs and OS in the NeoCT-RT patient group
RT for breast cancer. Material/Methods:
Patients undergoing reirradiation for lung lesions after prior postoperative breast cancer RT from 2011-2024 in a single cancer centre were retrospectively reviewed. Data on toxicity (CTCAEv5 grade 3-5) and death were extracted from patient records. To assess cumulative normal tissue doses, the dose of the previous treatment (RT1) was transferred to the reirradiation CT (RT2) using deformable image registration, followed by EQD2Gy dose rescaling ( α / β =3Gy) assuming no tissue recovery. Results: Forty-three consecutive patients were identified. Patients had a median age of 70 years at RT2, 77% had a performance status ≥ 1, and 33% were treated for locoregional breast cancer at RT1 (see Table 1 for further characteristics). Median time from RT1 to RT2 was 67 months (range: 8-138); median follow-up after RT2 was 32 months (1-104). Median OS for patients with NSCLC at RT2 was 53 months for those treated with stereotactic body RT (SBRT) and 69 months after long-course radiotherapy. In 31% of patients, the RT2 treatment target was within 2cm of the 50% iso-dose line of RT1 (tabel 1). No patients experienced severe (grade ≥ 3) adverse events after RT1. After RT2, 10 patients experienced grade 3 adverse events (5 cardiac events, 2 pneumonitis, 2 rib fractures, 1 esophagitis). For patients with cardiac events, mean EQD2Gyheart was 0.3Gy to 25.3Gy (median 2.2Gy), comparable to mean EQD2Gyheart from 0.1Gy to 18.5Gy (median 2.0Gy) delivered to patients without cardiac events. Only one cardiac event was definitely
Conclusion: A highly infiltrated post-treatment TME after NeoCT-RT was associated with improved OS, supporting the immunomodulatory potential of radiotherapy in resectable stage III NSCLC. High-TIL density (1/3 of cases) was associated with favorable outcomes after NeoCT-RT but not chemotherapy alone, suggesting that TILs reflect a more immunogenic TME and a potential biomarker in the neoadjuvant setting. References: Gataa I, Mezquita L, Rossoni C, Auclin E, Kossai M, Aboubakar F, Le Moulec S, Massé J, Masson M, Radosevic-Robin N, Alemany P, Rouanne M, Bluthgen V, Hendriks L, Caramella C, Gazzah A, Planchard D, Pignon JP, Besse B, Adam J. Tumour-infiltrating lymphocyte density is associated with favourable outcome in patients with advanced non-small cell lung cancer treated with immunotherapy. Eur J Cancer. 2021 Mar;145:221-229. doi: 10.1016/j.ejca.2020.10.017. Epub 2021 Jan 27. PMID: 33516050. Keywords: resectable NSCLC; TILs; outcomes
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