Genotype-Specific Differences in Circulating Tumor DNA Levels in Advanced NSCLC

Vincent K. Lam, Jianjun Zhang, Carol C. Wu, Hai T. Tran, Lerong Li, Lixia Diao, Jing Wang, Waree Rinsurongkawong, Victoria M. Raymond, Richard B. Lanman, Jeff Lewis, Emily B. Roarty, Jack Roth, Stephen Swisher, J. Jack Lee, Don L. Gibbons, Vassiliki A. Papadimitrakopoulou, John V. Heymach

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: Plasma-based circulating tumor DNA (ctDNA) is an established biomarker for molecular profiling with emerging applications in disease monitoring in multiple tumor types, including, NSCLC. However, determinants of ctDNA shedding and correlation with tumor burden are incompletely understood, particularly in advanced-stage disease. Methods: We retrospectively analyzed ctDNA-based and tissue-based genomic data and imaging from 144 patients with NSCLC. Tumor burden was quantified with computed tomography (CT) and brain magnetic resonance imaging for the overall cohort and 18F-fludeoxyglucose positron emission tomography-CT in a subset of patients. Results: There was a moderate but statistically significant correlation between ctDNA variant allele frequency and multiple imaging measures of tumor burden such as CT volume (rho = 0.34, p ≤ 0.0001) and metabolic tumor volume (rho = 0.36, p = 0.003). This correlation was strongest in KRAS-mutant tumors (rho = 0.56, p ≤ 0.001), followed by TP53 mutants (rho = 0.43, p ≤ 0.0001), and weakest in EGFR-mutated (EGFR+) tumors (rho = 0.24, p = 0.077). EGFR+ tumors with EGFR copy number gain had significantly higher variant allele frequency than EGFR+ without copy number gain (p ≤ 0.00001). In multivariable analysis, TP53 and EGFR mutations, visceral metastasis, and tumor burden were independent predictors of increased ctDNA shedding. Conclusions: Levels of detectable ctDNA were affected not only by tumor burden but also by tumor genotype. The genotype-specific differences observed may be due to variations in DNA shedding and cellular turnover. These findings have implications for the emerging use of ctDNA in NSCLC disease monitoring and early detection.

Original languageEnglish (US)
Pages (from-to)601-609
Number of pages9
JournalJournal of Thoracic Oncology
Volume16
Issue number4
DOIs
StatePublished - Apr 2021

Keywords

  • Cancer detection
  • Genotype
  • Liquid biopsy
  • Lung cancer
  • PET/CT
  • Tumor volume
  • ctDNA

ASJC Scopus subject areas

  • Oncology
  • Pulmonary and Respiratory Medicine

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