433 Prevalence of PD-L1 expression among patients with recurrent and metastatic head and neck squamous cell carcinoma in Taiwan

• Published in: Journal for immunotherapy of cancer 2022-11, Vol.10 (Suppl 2), p.A454-A454
• Main Authors: Chia-Jui Yen, Ming-Yu, Lien, Cheng, Rebecca, Yu-Wen, Su, Han-Nan, Lin, Wong, Michael Thomas, Poon, Song Ling, Chih-Yen Chien, Ruey-Long, Hong
• Format: Article
• Language: English
• Subjects: Apoptosis; Bladder cancer; Cancer therapies; Chemotherapy; Clinical significance; Head & neck cancer; Immunotherapy; Ligands; Medical prognosis; Metastasis; Squamous cell carcinoma
• ISSN: 2051-1426
• DOI: 10.1136/jitc-2022-SITC2022.0433

BackgroundTumor programmed death-receptor/ligand-1 (PD-1/PD-L1) expression negatively correlates with cancer prognosis and overall survival, 1-6 and has been shown to predict clinical responses to immunotherapy for head and neck cancers.7 In Taiwan, head and neck cancers continue to show a high prevalence associated with betel quid chewing, a practice endemic to the island. This study aims to evaluate the prevalence of PD-L1 expression in recurrent and metastatic head and neck squamous cell carcinoma (R/M HNSCC) patients in Taiwan.MethodsFor this multi-centered prospective study, we recruited R/M HNSCC patients who are aged 20 years or older, have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, are ineligible for re-irradiation or curative surgery, and had a biopsy obtained before treatment. PD-L1 expression measured by combined positive score (CPS) and tumor proportion score (TPS) was determined by the PD-L1 IHC 22C3 pharmDx™ kit. The primary endpoint was to estimate the prevalence of PD-L1 expression, characterized by CPS≥ 1. Exploratory analyses were conducted to evaluate PD-L1 positivity by CPS≥ 20 and TPS≥ 50%, and to explore the association of prior first- or second-line systemic treatment and PD-L1 expression.ResultsBetween December 2019 and February 2021, 280 patients from 4 centers were enrolled, including 264 (94.3%) males with median age of 58.0 years. Notably, 211 (75.4%) had a history of betel nut chewing. The primary sites were oral cavity in 192 cases (68.5%), followed by oropharynx 43 (15.4%), hypopharynx 26 (9.3%), and larynx 20 (7.1%). Among patients with oropharyngeal cancer, 13 (30.2%) were p16 positive. Prior to enrollment, 171 (61.1%) patients had received first-line systemic treatment and 68 (24.3%) second-line. The prevalence of PD-L1 (CPS≥ 1) was 94.3% (264/280) in the total cohort, 93.8% (198/211) in the betel nut exposed subgroup, and 96.6% (56/58) in the non-betel nut exposed subgroup. Furthermore, 46.1% (129/280) of all patients were CPS≥ 20, and 17.1% (48/280) were TPS≥ 50%. A total of 159 (93.0%) and 64 (94.1%) patients were CPS≥ 1 among those that received first-line and second-line systemic treatment, respectively.ConclusionsPD-L1 expression was observed in a vast majority (94.3%) of R/M HNSCC patients. There is no difference in PD-L1 prevalence between those with betel nut exposure history and betel nut non-exposed patients. PD-L1 prevalence also does not differ in those that had received prior f