Abstract 563
Background
HNSCC occurring in previously irradiated area have a poor prognosis. With immunotherapy, the inhibition of negative regulators of immune checkpoints programmed cell death ligand-1 (PD-L1) and CD8+ tumor-infiltrating lymphocytes (TILs) have been of greatest importance for antitumor immune response. Yet, the immune landscape of pretreated area remains poorly documented and should be investigated, especially since locoregional recurrences have recently been described as a predominant site of hyperprogression. We aimed to assess the tumoral microenvironment in terms of biomarkers for tumor immune response in irradiated area compared to de novo tumors.
Methods
This retrospective monocentric study analyzed 100 HNSCC tumor tissues from patients who had undergone surgery between January 2010 and November 2017. We compared the immune microenvironment in 50 de novo tumors and 50 tumor recurrence occurring within irradiated area. Formalin-fixed and paraffin embedded tumor tissue samples were reviewed by an experimented pathologist for immunohistochemistry. We assessed p16 status, CD3+ and CD8+ TILs and PD-L1 expression on tumor and immune cells, in stromal and intratumoral components.
Results
The density of CD3+ TILs was significantly lower, whether in intratumoral or stromal region within irradiated areas (p = 0.003 and p = 0.020 respectively). The expression of CD8+ TILs was not significantly different between the two cohorts. The percentage of tumor cells expressing PD-L1 TC (TPS=1%) was significantly lower in tumours developed within irradiated area than in de novo tumors (56.0% vs 86.0%) (p < 0.001). Immune cells expressing PDL-1 were less frequent in tumors within irradiated areas. Predominant microenvironment type in irradiated area cohort was adaptative immune resistance.
Conclusions
There were persistence of cytotoxic cells and lower expression of PD-L1 and CD3+ TILs in tumors within irradiated area. This study provides first hypothesis to explain the fact that these lesions are less responsive to immunotherapy although they may still have antitumor capacity. The assessment of predictive biomarkers in patients treated by immunotherapy in randomized trials is required.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Dr Lionnel Geoffrois.
Funding
Has not received any funding.
Disclosure
C. Borel: Honoraria (self): Merck; Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: BMS. L. Geoffrois: Honoraria (self), Travel / Accommodation / Expenses: MSD; Honoraria (self), Travel / Accommodation / Expenses: BMS; Honoraria (self): Ipsen; Honoraria (self): Novartis; Travel / Accommodation / Expenses: Merck Serono. All other authors have declared no conflicts of interest.
Resources from the same session
1084 - Dissociated responses in patients with metastatic solid tumors treated with immunotherapy
Presenter: Pauline Vaflard
Session: Poster Display session 3
Resources:
Abstract
4600 - Patterns and outcomes related to rapid progressive disease in a cohort of advanced solid tumors treated with immune checkpoint inhibitors (ICIs).
Presenter: Lucio Ghiglione
Session: Poster Display session 3
Resources:
Abstract
3547 - Real World Outcomes of Immune-Related Adverse Events (irAEs) among Patients Receiving Immune Checkpoint Inhibitors (ICIs) in Hospital Settings
Presenter: Saby George
Session: Poster Display session 3
Resources:
Abstract
1124 - Sex-based heterogeneity of efficacy of anticancer immunotherapy
Presenter: Fabio Conforti
Session: Poster Display session 3
Resources:
Abstract
4133 - Comparative efficacy and safety of PD-1/PD-L1 inhibitors for patients with solid tumors: a systematic review and Bayesian network meta-analysis
Presenter: Qingyuan Huang
Session: Poster Display session 3
Resources:
Abstract
2548 - Excess weight and efficacy of anti-PD-1 antibodies in advanced cancer patients
Presenter: Jacobo Rogado
Session: Poster Display session 3
Resources:
Abstract
2228 - Safety and efficacy of anti-PD-1 inhibitor ABBV-181 in lung and head and neck carcinoma
Presenter: Antoine Italiano
Session: Poster Display session 3
Resources:
Abstract
2333 - Efficacy and safety of immune checkpoint inhibitors (ICIs) for treatment of advanced solid tumours in octogenarian patients
Presenter: Soraya Mebarki
Session: Poster Display session 3
Resources:
Abstract
4847 - Association of programmed cell death 1 (PD-1) inhibitor therapy with overall survival (OS) in stage IV melanoma treated with targeted therapies
Presenter: Aracelis Torres
Session: Poster Display session 3
Resources:
Abstract
2215 - Clinical outcomes of immune checkpoint inhibitors in older and younger patients with advanced solid tumours in a real-life setting
Presenter: Pauline Corbaux
Session: Poster Display session 3
Resources:
Abstract