CD8+ T Cell Infiltration Predicts Chemoradiosensitivity in Nasopharyngeal or Oropharyngeal Cancer

CD8+ T Cell Infiltration Predicts Chemoradiosensitivity in Nasopharyngeal or Oropharyngeal Cancer:

Objectives

Limited information exists regarding the associations between pre‐existing immune parameters in the tumor immune microenvironment (TIM) and either chemoradiosensitivity or prognosis for patients with squamous cell carcinoma of the nasopharynx or oropharynx involving virus‐related or nonvirus‐related tumors.

Study Design

Retrospective cohort study.

Methods

We retrospectively reviewed 141 patients with EBV+, p16+, or EBV− and p16− statuses who are receiving chemoradiotherapy. We performed immunohistochemistry using pretreatment biopsy specimens to analyze the programed death ligand 1 (PD‐L1) levels in tumor and immune cells and CD8+ tumor‐infiltrating lymphocyte (TIL) density. We evaluated chemoradiosensitivity and prognosis with respect to these immune‐related parameters.

Results

Virus‐related tumors showed associations with both PD‐L1 expression and high CD8+ TIL density. Patients with higher CD8+ TIL density or greater numbers of PD‐L1+ tumor and immune cells showed significant rates of favorable local recurrence‐free survival (LRFS), progression‐free survival (PFS), and overall survival (OS). Multivariate analyses demonstrated that higher CD8+ TIL density is an independent, significant, and favorable predictive factor for LRFS (P = .005) and OS (P = .003), although it is not a significant predictor of PFS (P = .077).

Conclusions

Higher CD8+ TIL density represents a useful and favorable biomarker of chemoradiosensitivity in patients receiving chemoradiotherapy for nasopharyngeal or oropharyngeal cancer.

Level of Evidence

3 Laryngoscope, 2020