Chemoradiation therapy alters the PD-L1 score in locoregional recurrent squamous cell carcinomas of the head and neck.

PD-L1 testing guides therapeutic decision-making for head and neck squamous cell carcinoma (HNSCC). We sought to understand whether chemoradiation therapy (CRT) influences the PD-L1 combined positive score (CPS) and other biomarkers of response to immunotherapy. PD-L1 expression was assessed using immunohistochemistry, and bulk RNA sequencing was performed on 146 HNSCC patients (65 primary sites, 50 paired local recurrences, and 31 paired regional recurrences). PD-L1 was scored using the CPS of ≥1, ≥20, and ≥50. Overall, 98 %, 54 %, and 17 % of HNSCCs had a CPS ≥1, ≥20, and ≥50, respectively. When using a cut-off of ≥1, CRT did not significantly change CPS at the locoregional recurrent site. However, there were significant changes when using CPS ≥20 or ≥50. The CPS changed for 32 % of patients when using a CPS ≥20 (p < 0.001). When using a CPS ≥50, there was a 20-23 % (p = 0.0058-0.00067) discordance rate at the site of locoregional recurrence. Oral cavity cancers had a significantly higher discordant rate than other primary sites for CPS ≥50, 44 % (8/18, p = 0.0058) and 58 % (7/12, p = 0.00067) discordance at the site of local and regional recurrence, respectively. When evaluating the 18 gene IFN-ɣ signature predictive of response to anti-PD-1 blockade, there was a statistically significant increase in the IFN-ɣ signature in recurrent larynx cancer (p = 0.02). Our study demonstrates that when using a higher cut-off of CPS ≥20 and ≥50, a repeat biopsy may be warranted after CRT for local and regional recurrent HNSCCs.

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Déclaration de conflit d'intérêts

Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: S.I.P. has received consultancy payments from Abbvie, Astrazeneca/MedImmune, Cue Biopharma, Fusion Pharmaceuticals, MSD/Merck, Newlink Genetics, Oncolys Biopharma, Replimmune, Scopus Biopharma, and Sensei Bio. S.I.P. has received grants/research support from Abbvie, Astrazeneca/MedImmune, Cue Biopharma, Merck, and Tesaro. R.B.B. has received consultancy payments from Merck, Regeneron, Macrogenics, and Bristol Myers Squibb. R.B.B. has received institutional research grants from Bristol Myers Squibb. All other authors declare no potential conflicts of interest.