Analysis of PD-L1 expression in locally advanced head and neck squamous cell carcinoma and its correlation with the efficacy of neoadjuvant immunotherapy + chemotherapy: A retrospective real-world study.

Abstract

6074 Background: The incidence rate of HNSCC in Hunan China are notably higher than in other regions, likely due to the high prevalence of betel nut chewing. Therefore, we conducted a study to examine the PD-L1 expression in newly diagnosed locally advanced (stage III-IVB) HNSCC patients. Methods: 1. We conducted a retrospective analysis of the PD-L1 expression (represented as CPS) in pre-treatment biopsy tissues from locally advanced HNSCC. 2. 57 patients received neoadjuvant treatment consisting of nab-paclitaxel+ cisplatin+ pembrolizumab. The efficacy of the treatment was evaluated using pathology assessments. Results: 1. A total of 373 patients were included. The top five primary sites of the tumors were the tongue(32.17%), Buccal oris (20.91%), oropharynx (10.19%), hypopharynx(9.92%), and gingiva(7.77%). The proportion of patients with PD-L1 CPS≥20 (55.23%) was significantly higher than the 43.20% reported in the KEYNOTE-048 study. Furthermore, the subgroup was even higher in the buccal oris (70.51%) and gingiva (72.41%). 2. A total of 57 patients were tested for PD-L1 CPS and received neoadjuvant treatment.After surgery, 22/57 (38.60%) achieved pathological complete response (pCR) or major pathological response (MPR), 29/57 (50.88%) achieved partial pathological response (pPR), resulting in an overall response rate (ORR) of 89.47%. In the PD-L1 CPS ≥20 group, the ORR was as high as 91.89% (34/37). 3. Among the 57 patients, 36 patients had lymph node metastasis. After treatment, 15/36 patients (41.67%) achieved pCR/MPR in lymph nodes, 7/36 patients (19.44%) achieved pPR, resulting in an ORR was 61.11% (22/36). Conclusions: 1. The oral cavity is the most common primary in HNSCC in Hunan,China. In the locally advanced , the proportion of PD-L1 CPS ≥20 is higher than reported in other studies. 2. Regardless of PD-L1 expression, neoadjuvant treatment with nab-paclitaxel+ cisplatin+ pembrolizumab has shown a high rate of local disease control in newly diagnosed HNSCC patients. Additionally, the use of neoadjuvant therapy has improved the delineation of surgical safety margins, leading to 100% R0 resections in all 57 patients. 3. The response of the primary lesion in patients treated with neoadjuvant therapy is better than that of the lymph node. Patients with a well-responding primary lesion but multiple lymph node metastases should be closely monitored for the possibility of short-term systemic metastasis. [Table: see text]