ESTRO 2024 - Abstract Book

S1750

Clinical - Lung

ESTRO 2024

Purpose/Objective:

Tyrosine kinase inhibitors (TKIs) are the backbone of treatment for patients with metastatic non-small cell cancer lung (NSCLC) harbouring the epidermal growth factor receptor (EGFR) mutation or the anaplastic lymphoma kinase (ALK) rearrangement [1, 2]. However, a common problem is acquired resistance leading to progression [3, 4], typically resulting in a change of systemic therapy. Some patients progress in limited metastatic sites where a local therapy may eliminate the resistant clones, and the patient can maintain the same TKI treatment [5-7]. The current study aims to retrospectively review the efficacy of such a strategy in a single institution.

Material/Methods:

In this retrospective single center study, patients with EGFR or ALK mutated NSCLC were included if 1) they were treated with any line of TKI at the Department of Oncology, Herlev Hospital during 2016-2022, and 2) they received local therapy (LT) to any progressive site while maintaining the same TKI. Baseline (at TKI initiation) and local therapy characteristics were obtained. Time to local therapy (TLT) was defined as time from initiation of TKI treatment until first LT. Progression-free survival after LT (PFS2) was defined as time from the first LT until progression or death. Time to end of TKI treatment (TETT) was defined as time from first LT until the end of current TKI. If a patient was dead or lost to follow-up without knowing the precise TKI cessation date, the latest follow-up date was used for TETT.

TLT, PFS2, and TETT were evaluated for each TKI regimen, i.e., a patient could be included in the above time analyses more than once.

Results:

Forty-five patients were included in the analysis, including 14 patients with ALK rearrangements and 31 patients with EGFR mutations. Baseline characteristics are shown in Table 1.

Mutation ALK , N = 14

Overall , N = 45

Characteristic

EGFR , N = 31

Age , Median (Range)

68 (33-89)

60 (33-89)

68 (34-86)

Male

25 (56%)

9 (64%)

16 (52%)

Smoking Status Never Smoker

23 (51%) 22 (49%)

9 (64%) 5 (36%)

14 (45%) 17 (55%)

Former Smoker

Histology

Adenocarcinoma

41 (91%)

14 (100%)

27 (87%)

Adenosquamous

4 (8.9%)

0 (0%)

4 (13%)

Carcinoma

Previous

Curative

6 (13%)

1 (7.1%)

5 (16%)

Treatment

Metastases Lung & Mediastinal 32 (71%)

11 (79%)

21 (68%)