Abstract 77P
Background
Radiotherapy (RT) and chemotherapy can induce immune responses, but not much is known regarding treatment-induced immune changes in patients. The aim of this exploratory study was to identify immune signatures that are associated with progression free survival (PFS).
Methods
In a prospective study, (NCT02921854) patients with stage I (n=26) and stage III (n=18) NSCLC were included. Stage I patients were treated with stereotactic body radiation therapy (SBRT) and stage III patients with concurrent chemoradiotherapy (CCRT; cisplatin/etoposide, 60-66 Gy). Blood samples were collected before, during, and after RT and were screened by plasma proteomic analysis for >1000 proteins using Proximity Extension Assay (Olink Proteomics). Data were analyzed using the cox-proportional hazards model and Benjamini and Hochberg multiple hypothesis correction. A functional assay was used to assess the peripheral immuno-modulatory activity (e.g. IFN response).
Results
In stage I NSCLC, CD244 was identified as a potential prognostic biomarker (HR:10.2, 95%CI: 1.8-57.4). Patients with increased expression levels of CD244 before the start of RT have a lower PFS compared to those with lower CD244 levels (19.1 vs 27.2 months). Potential predictive biomarkers that have been identified include IL-10 (HR:11.8, 95%CI: 2.4-58.1) and Oncostatin M (HR:3.2, 95%CI:1.5-7.1). However, the circulating levels of all identified proteins were not affected by RT as the observed differences were already present at baseline. Furthermore, PFS was not associated with activation of peripheral IFN response. In patients with stage III NSCLC, no potential predictive and prognostic biomarkers were identified despite the dynamic expression of immune proteins during RT.
Conclusions
In this exploratory study, we observed that baseline expression of several immunogenic proteins might be a determining factor in predicting PFS in stage I NSCLC, treated with SBRT. For CCRT patients, the immunosuppressive effects of chemotherapy may nullify any relevant RT-induced immune changes. This study forms the basis for additional studies concerning immunological biomarkers.
Clinical trial identification
NCT02921854.
Editorial acknowledgement
Legal entity responsible for the study
Maastro.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.