Preoperative prediction of pathologic response to neoadjuvant immunotherapy in resectable locally advanced head and neck squamous cell carcinoma using multiparametric MRI

Accurately predicting the pathologic response to neoadjuvant immunotherapy in patients with head and neck squamous cell carcinoma (HNSCC) prior to surgery is crucial for guiding clinical decision-making and minimizing potential ineffective treatments and unnecessary toxicity. This study aimed to assess the effectiveness of utilizing quantitative changes observed in MRI post-neoadjuvant immunotherapy as a predictive tool for determining the pathologic response in resectable locally advanced HNSCC patients.

Twenty patients with resectable locally advanced HNSCC recruited in the prospective phase lb clinical trial were included in the current retrospective analysis. In this current analysis, patients underwent contrast-enhanced MRI and diffusion-weighted MRI (DWI) scanning before neoadjuvant immunotherapy and radical resection of the tumor, respectively. Response to neoadjuvant immunotherapy was based on histopathological evaluation of the resected specimen. The primary tumor volume and the apparent diffusion coefficient (ADC) value were measured. Fisher’s exact test and the Mann-Whitney U-test were used to compare the two groups of treatment response (good response and poor response). The area under the receiver operating characteristic curve (ROC) was used to assess the ability of relative changes in ADC value and tumor volume in discriminating between different pathologic response groups.

Good response was found in 35% of all patients. After neoadjuvant immunotherapy, significant differences were observed in the relative changes of primary tumor volume (ΔV_primary, p = 0.04) and DWI parameters (ΔADC_primary, p = 0.03) between the groups exhibiting good and poor responses. When the relative changes in tumor volume were used to predict treatment response, the area under the curve (AUC) was 0.97, with 85.70% sensitivity and 100% specificity. Change in ADC value achieved an AUC of 0.90 with a sensitivity of 71.40% and a specificity of 100% for the prediction of treatment response.

Changes in tumor volume and ADC value after neoadjuvant immunotherapy can help identify patients with good responses to neoadjuvant immunotherapy in HNSCC.