978P - Prevalence, pattern, and impact of PD-L1 expression and HPV-status in head and neck squamous cell carcinoma

Date 09 October 2016
Event ESMO 2016 Congress
Session Poster display
Topics Head and Neck Cancers
Presenter Teeranuch Chureemas
Citation Annals of Oncology (2016) 27 (6): 328-350. 10.1093/annonc/mdw376
Authors T. Chureemas1, N. Larbcharoensub2, J. Juengsamarn1, T. Layangkool3, C. Jiarpinitnun4, P. Chansriwong1, N. Trachu5, P. Pattaranutaporn4, N. Ngamphaiboon1
  • 1Medical Oncology, Ramathibodi Hospital, 10400 - Bangkok/TH
  • 2Pathology, Ramathibodi Hospital, 10400 - Bangkok/TH
  • 3Internal Medicine, Ramathibodi Hospital, 10400 - Bangkok/TH
  • 4Radiation Oncology, Ramathibodi Hospital, 10400 - Bangkok/TH
  • 5Molecular Biology, Ramathibodi Hospital, 10400 - Bangkok/TH

Abstract

Background

Early phase clinical studies showed activities of anti PD-L1/PD-1 antibody in head and neck squamous cell carcinomas (HNSCC). PD-L1 expression was extensively evaluated as a biomarker though no standardized method of detection has been defined. HPV status is a well-established prognostic maker of HNSCC. Prevalence, pattern, and impact of PD-L1 expression in HPV-associated HNSCC remain unclear and may vary in different ethnicity.

Methods

HNSCC patients treated at the Ramathibodi Cancer Center between 1/2007 and 12/2013 were identified through the cancer registry database. Patient characteristics, treatments, and survivals were abstracted. Archrival formalin-fixed paraffin-embedded (FFPE) tissues were retrieved for PD-L1 and p16 analyses. PD-L1 expression was evaluated by using an anti-human PD-L1 rabbit monoclonal antibody (clone SP142; Ventana) on an automated staining platform (Ventana). PD-L1 was evaluated on tumor cells (TC) and tumor-infiltrating immune cells (IC), and scored ranging between 0-100%. For overall survival (OS) analysis, specimens were scored as ≥5% on TCs or ICs to define PD-L1 positive. HPV status was determined by p16 immunohistochemistry.

Results

204 HNSCC patients with available FFPE tissues were analyzed. PD-L1 on TCs was expression (≥1%) and highly expressed (≥50%) in 72.2% and 18.4% of patients, respectively. With a definition of PD-L1 ≥5% on TCs or ICs, 79.7% of patients was considered as PD-L1+. No statistically difference in patient characteristics between PD-L1 positive and negative, except age ≥65 was associated with a higher incidence of PD-L1 positive (53.4% vs 21.1%; p = 0.001). Overall, 74 patients (36.3%) was p16+. No association of PD-L1 and p16 was observed (p = 0.116). OS was significantly longer in PD-L1+ patients (34.5 vs 21.5 months; p = 0.044). In subgroup analysis of PD-L1/p16 status, OS was superior in patients with +/ + , +/-, -/-, and -/ + , respectively (67.4 vs 23.6 vs 21.5 vs 15.8 months; p = 0.006).

Conclusions

A high prevalence of PD-L1 expression was observed in HNSCC. PD-L1 expression was a strong prognostic maker for OS, especially in p16+ HNSCC patients. These results support further development of anti PD-L1/PD-1 antibody in HNSCC.

Clinical trial identification

Legal entity responsible for the study

Ramathibodi hospital

Funding

Ramathibodi Cancer Center

Disclosure

All authors have declared no conflicts of interest.