Interleukin-6 as surrogate marker for imaging-based hypoxia dynamics in patients with head-and-neck cancers undergoing definitive chemoradiation—results from a prospective pilot trial

Purpose Intratumoral hypoxia increases resistance of head-and-neck squamous cell carcinoma (HNSCC) to radiotherapy. [18F]FMISO PET imaging enables noninvasive hypoxia monitoring, though requiring complex logistical efforts. We investigated the role of plasma interleukin-6 (IL-6) as potential surrogate parameter for intratumoral hypoxia in HNSCC using [18F]FMISO PET/CT as reference. Methods Within a prospective trial, serial blood samples of 27 HNSCC patients undergoing definitive chemoradiation were collected to analyze plasma IL-6 levels. Intratumoral hypoxia was assessed in treatment weeks 0, 2, and 5 using [18F]FMISO PET/CT imaging. The association between PET-based hypoxia and IL-6 was examined using Pearson’s correlation and multiple regression analyses, and the diagnostic power of IL-6 for tumor hypoxia response prediction was determined with receiver-operating characteristic analyses. Results Mean IL-6 concentrations were 15.1, 19.6, and 31.0 pg/mL at baseline, week 2 and week 5, respectively. Smoking (p=0.050) and reduced performance status (p=0.011) resulted in higher IL-6 levels, whereas tumor (p=0.427) and nodal stages (p=0.334), tumor localization (p=0.439), and HPV status (p=0.294) had no influence. IL-6 levels strongly correlated with the intratumoral hypoxic subvolume during treatment (baseline: r=0.775, p<0.001; week 2: r=0.553, p=0.007; week 5: r=0.734, p<0.001). IL-6 levels in week 2 were higher in patients with absent early tumor hypoxia response (p=0.016) and predicted early hypoxia response (AUC=0.822, p=0.031). Increased IL-6 levels at week 5 resulted in a trend towards reduced progression-free survival (p=0.078) and overall survival (p=0.013). Conclusion Plasma IL-6 is a promising surrogate marker for tumor hypoxia dynamics in HNSCC patients and may facilitate hypoxia-directed personalized radiotherapy concepts. Trial registration The prospective trial was registered in the German Clinical Trial Register (DRKS00003830). Registered 20 August 2015

244 Genomic determinants of response to chemoradiation and durvalumab consolidation for stage III non-small cell lung cancer

BackgroundDurvalumab consolidation after chemoradiation for unresectable stage III non-small cell lung cancer (NSCLC) improves overall survival. However, up to 25% of patients progress within 18 months following durvalumab consolidation. Little is known regarding the genomic determinants of response to therapy.1 2MethodsWe retrospectively reviewed medical records of 76 patients with stage III NSCLC who received definitive chemoradiation and durvalumab consolidation between 2015–2020 at a large tertiary academic center. Tumor characteristics, molecular profiling, and clinical outcomes including response, progression-free survival (PFS), and overall survival (OS) were documented in an IRB-approved database. Outcomes were assessed by molecular alterations identified from diagnostic biopsy samples using Kaplan-Meier analysis.ResultsOf 76 patients with stage III NSCLC treated with definitive chemoradiation and durvalumab consolidation, 74 were evaluable for PFS and OS. Median age at diagnosis was 66.5 years and 43% were women (n=32). Histology included adenocarcinoma (55%, n=41) and squamous cell carcinoma (32%, n=24). Median follow-up time was 23.0 months from start of durvalumab. The cohort’s median PFS was 15.9 months with 36 patients having documented radiographic progression. Overall survival for the cohort was 32.0 months with 28 deaths. Molecular profiling was performed at time of diagnosis in 35 patients (47%), of which 30 had adenocarcinoma histology. 18 patients had KRAS mutations including KRAS p.G12C (n=8), which were mutually exclusive with 8 patients who had other clinically targetable alterations (EGFR mutations n=1, ALK fusion n=1, RET fusion n=1, MET exon 14 skipping mutation n=1, or ERBB2 mutation n=4). Three patients had non-targetable mutations (BRAF non-p.V600E, STK11, KEAP1) and the remaining six patients lacked an identifiable alteration. There was no significant difference in PFS (p=0.92 by log-rank) or OS (p=0.36 by log-rank) between patients with KRAS mutations, other targetable alterations, non-targetable mutations, or those without molecular profiling. Within patients with KRAS mutations, there was no significant difference in PFS (p=0.33 by log-rank) or OS (p=0.69 by log-rank) when comparing KRAS p.G12C to non-p.G12C mutations.ConclusionsOur study of real-world cohort of patients with stage III NSCLC examined genomic determinants of response to treatment with definitive chemoradiation and durvalumab. Results from this retrospective study suggest that patients with KRAS-mutated tumors derive similar benefit from therapy than patients with other targetable, non-targetable or no identifiable genomic alterations. Future directions for this cohort include analysis of post-progression therapy, subgroup analysis comparing genomic alterations to patterns of progression, and examination of molecular signatures of patients with progression.ReferencesAntonia SJ, Villegas A, Daniel D, et al. Durvalumab after chemoradiotherapy in stage III non–small-cell lung cancer. N Engl J Med 2017;377(20):1919–1929. doi:10.1056/NEJMoa1709937Faivre-Finn C, Vicente D, Kurata T, et al. Four-year survival with durvalumab after chemoradiotherapy in stage III NSCLC—an update from the PACIFIC trial. Journal of Thoracic Oncology 2021;16(5):860–867. doi:10.1016/j.jtho.2020.12.015Ethics ApprovalThis retrospective chart review study has obtained ethics approval from the Institutional Review Board at the Johns Hopkins School of Medicine (number: IRB00232313).