New research examines how circulating tumor DNA testing could help detect cancer recurrence, track treatment response, and identify resistance across multiple cancer types.

Guardant Health and its research collaborators will present 25 abstracts, including five rapid oral presentations, at the European Society for Medical Oncology (ESMO) Congress 2026, held Oct 23-27 in Madrid, Spain. The research showcases advances in methylation-based circulating tumor DNA (ctDNA) monitoring and liquid biopsy technology across lung, colorectal, and gastric cancers.

The featured presentations cover tissue-free minimal residual disease (MRD) surveillance, treatment response evaluation, and therapy resistance research, including independent investigations conducted by academic institutions, industry partners, and European public-private collaborators.

“At ESMO, we will showcase how InfinityAI is advancing our portfolio, strengthening the clinical relevance of our data, and delivering value to patients, healthcare professionals, and biopharma partners,” says Helmy Eltoukhy, Guardant Health chairman and co-CEO, in a release.

Oral Presentations Focus on ctDNA Guidance and Resistance

Several rapid oral presentations highlight the application of liquid biopsy assays in therapy guidance and patient stratification:

  • Gastric and Gastroesophageal Junction Cancer: Data from the FORTITUDE study (Rapid Oral 283RO) evaluate bemarituzumab in patients with advanced gastric and gastroesophageal junction cancer based on fibroblast growth factor receptor 2 (FGFR2) amplification status, indicating that FGFR2 amplification can identify a more treatment-sensitive patient subgroup.
  • EGFR-Mutant Lung Cancer: The PACE-LUNG study (Rapid Oral LBA73), a multicenter Phase II trial, examines ctDNA-guided treatment intensification in untreated advanced or metastatic EGFR-mutant non-small cell lung cancer (NSCLC). The study evaluates adding chemotherapy for patients with persistent EGFR-mutant ctDNA in plasma at Week 3 after starting first-line osimertinib.
  • Lorlatinib Resistance Profiling: An analysis from the CROWN study (Rapid Oral 2636RO) characterizes resistance mechanisms and predictors of early disease progression and long-term response to lorlatinib. Results suggest baseline genomic complexity and on-treatment methylation-based assay shifts may identify patients at elevated risk of early progression.

Post-Surgical MRD and Colorectal Cancer Monitoring

In addition to oral sessions, poster presentations highlight real-world utility and post-surgical monitoring:

  • MRD in NSCLC: An exploratory analysis from the NADIM II trial (Poster 2566P) examines post-surgical MRD and pathological complete response (pCR) following perioperative nivolumab in resectable Stage III NSCLC. Pathological complete response correlated with MRD negativity and five-year survival. Among patients without pCR, MRD negativity identified individuals with favorable long-term outcomes, while detectable MRD identified high risk for early disease recurrence.
  • Anti-EGFR Rechallenge in Colorectal Cancer: A Phase 2 study with MD Anderson Cancer Center (Poster 4403P) utilized serial Guardant360 Liquid testing to track clonal and subclonal resistance during anti-EGFR rechallenge in metastatic colorectal cancer, differentiating biological resistance evolution from fluctuating ctDNA concentrations.
  • Turnaround Time Analysis: A real-world basic science analysis (Poster 424P) evaluates the operational impact of blood draw weekday on turnaround time for the Guardant360 CDx liquid biopsy assay.

European Laboratory Partnerships

The presentations also reflect Guardant Health’s ongoing work to expand test access through public-private partnerships established since 2020 with European institutions, including The Royal Marsden NHS Foundation Trust in the UK, Vall d’Hebron Institute of Oncology in Spain, and Policlinico Gemelli in Italy. These agreements focus on localizing advanced diagnostic testing, establishing clinical and economic evidence, and expanding regional reimbursement and diagnostic adoption.

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