PD-L1 expression in anogenital and oropharyngeal squamous cell carcinomas associated with different...

Little research has been done on clinicopathological characteristics and human papillomavirus (HPV) status of anogenital and oropharyngeal squamous cell carcinomas (SCC) with a strong expression of programmed death ligand 1 (PD-L1) in tumor cells. Therefore, we conducted this meta-analysis.

We performed a comprehensive research in PubMed, Embase and Cochrane databases up to 30 September 2020. The effect size was hazard ratio (HR) with 95% confidence interval (CI) for overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS). The pooled odds ratio (OR) with 95% CI were used to assess the association between PD-L1 expression and clinicopathological features along with HPV status.

A total of 2003 cases (944 anogenital and 1059 oropharynx SCC patients) were included. High PD-L1 expression in anogenital SCC cases were associated with advanced age (OR = 1.63, 95% CI: 1.04-2.58) and HPV negativity (OR = 0.47, 95% CI: 0.31-0.71). Besides, PD-L1 positive anogenital SCC cases held a significantly declined OS (HR = 2.18, 95% CI: 1.37-3.47) and CSS (HR = 2.45, 95% CI: 1.30-4.65). For oropharynx SCC, PD-L1 was more frequent in younger and HPV positive patients (OR = 0.60, 95% CI: 0.37-0.98; OR = 3.01, 95% CI: 1.78-5.09) and PD-L1 expression was relevant to better OS and DFS (HR = 0.76, 95% CI: 0.60-0.97; HR = 0.50, 95% CI: 0.33-0.75).

The meta-analysis demonstrated that in anogenital SCC, PD-L1 positivity had to do with a worse outcome, which might attribute to advanced age, higher tumor grade, lymph node metastasis and HPV negativity, while in oropharynx cancer, PD-L1 expression was related to better prognosis for the reason that PD-L1 was less frequent in the aged and negative HPV status.