Multi-dimensional cell-free DNA-based liquid biopsy for sensitive detection of head and neck squamous cell carcinomas.

Abstract

e18054 Background: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type worldwide. The mortality from HNSCC is closely linked to stage. However, the majority of HNSCC patients were diagnosed at an advanced stage. Therefore, a non-invasive assay for the early detection of HNSCCs is highly desirable for reducing the associated mortality. Methods: We collected a study cohort of 281 participants including 140 pathologically confirmed with head and neck squamous cell carcinomas (HNSCCs) and 141 with non-cancerous conditions. A plasma sample was collected from each participant along with general health screening examinations before any invasive examinations. We performed low-pass whole-genome sequencing with plasma samples and profiled three types of cell-free DNA (cfDNA) characteristics, fragment size pattern (FSP), copy number variation (CNV), and single nucleotide substitution (SNS). We developed an ensemble model with these differential profiles to identify HNSCC patients from non-cancer individuals. We further collected a validation cohort consisting of 90 HNSCC patients and 95 non-cancer individuals to validate the cfDNA-based assay. Results: The liquid biopsy assay that incorporated three types of cfDNA characteristics was able to identify HNSCC patients from non-cancer individuals at an AUROC of 0.989 in the study cohort and 0.984 in the validation cohort. At a specificity of 95.7% (135/141), it achieved a sensitivity of 95.7% (134/140) in the study cohort. With this threshold (0.580), in the validation cohort, 93.7% (89/95) of non-cancer individuals and 93.3% (84/90) of HNSCC patients were correctly identified. Specifically, the sensitivities in early stage (I&II) HNSCCs were 94.5 % (52/55) and 87.5% (28/32) in the study and validation cohort, respectively. Of note, the inferred probabilities of cancer showed consistent trends to increase with pathological stages in both cohorts (P=0.032 and 0.047, respectively). On the contrary, the differentiation grades and sub-locations did not significantly affect the performance of the assay. Conclusions: We introduced a liquid biopsy assay using multiple dimensions of cfDNA characteristics that could accurately identify HNSCCs from non-cancerous conditions. As a cost-effective non-invasive approach, it may be conveniently incorporated into annual general physical examinations to provide supplementary information about the risk of HNSCCs.