82P - Predictive biomarkers for neoadjuvant immunochemotherapy efficacy in locally advanced cancer patients: A retrospective analysis based on changes in tumor shrinkage rate and lymphocyte count

Background

Neoadjuvant immunochemotherapy (NICT) has been shown to effectively increase the proportion of pathologic complete response (pCR) in locally advanced HNSCC, driver-gene-negative NSCLC, and esophageal squamous cell carcinoma. Nonetheless, accurately predicting which patients will benefit most from this treatment strategy remains a significant challenge.

Methods

This retrospective analysis includes 485 patients with locally advanced cancer who were treated with NICT at our center from January 2020 to January 2024. Based on pre- and post-neoadjuvant treatment imaging data, patients were divided into groups according to tumor shrinkage: greater than 50%, 30% to 50%, and less than 30%. The study also examined PD-L1 expression levels and changes in lymphocyte counts pre and post treatment , to analyze their correlation with pCR rates.

Results

ESCC (147 cases): The pCR rate was 25% among patients with tumor shrinkage over 50%, significantly higher than that in patients with shrinkage less than 30% (pCR rate 4.2%). The pCR rate in the group with an increase in lymphocyte count (14.1%) was significantly higher than in the group with a decrease (6.9%).NSCLC (176 cases): Primarily treated with a PC regimen consisting of carboplatin and paclitaxel. The pCR rate was 57.8% in patients with more than 50% tumor shrinkage, significantly higher compared to those with less than 30% shrinkage (pCR rate 4.8%). The group with increased lymphocyte counts (41.5%) had a better pCR rate than the decreased group (30.1%). HNSCC (162 cases): Patients with over 50% tumor shrinkage had a pCR rate of 69.8%, compared to 21.1% in those with less than 30% shrinkage. The pCR rate in the lymphocyte increased group (47.8%) was slightly lower than in the decreased group (59.0%). Additionally, initial CPS and TPS scores did not show significant correlation with pCR across the three types of cancer.

Conclusions

Tumor shrinkage rates and changes in lymphocyte counts are effective predictive biomarkers for the efficacy of NICT. Significant tumor shrinkage and increased lymphocyte numbers correlate with higher pCR rates, helping to identify patients who may benefit from NICT.

Legal entity responsible for the study

Zhanjie Zhang.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.