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Genetic research

Circulating Tumor DNA Detection in Rectal Cancer: Study Results

Strategic Insights

— 1 min read

Researchers at the Applied Tumor Genomics Research Program have published new study results on the use of circulating tumor DNA (ctDNA) to identify rectal cancer patients who may benefit from neoadjuvant and adjuvant therapy. The study compared two methods for detecting ctDNA: droplet digital PCR (ddPCR) and next-generation sequencing (NGS). The research found that ddPCR detected ctDNA in 58.5% of patients before surgery, while NGS detected it in 36.6% of patients. The study also found that a positive ctDNA result was associated with higher clinical tumor stage and lymph node positivity.

Key Takeaways:

  • The study used a development group of 41 patients and a validation group of 26 patients to compare ddPCR and NGS for ctDNA detection in localized rectal cancer.
  • ddPCR detected ctDNA in 24/41 (58.5%) of patients before surgery, while NGS detected it in 15/41 (36.6%) patients (p = 0.00075).
  • In the validation group, 21/26 (80.8%) patients had detectable ctDNA in the pre-therapy plasma.
  • Postoperative ddPCR did not detect ctDNA before most recurrences.
  • The study concluded that ddPCR detects ctDNA from pre-therapy plasma at a satisfactory level in advanced rectal cancers.
  • A practical oligomarker ctDNA test for localized rectal cancer was developed, suitable for clinical workflow.

Statistics:

  • 58.5% of patients had detectable ctDNA in the pre-therapy plasma using ddPCR.
  • 36.6% of patients had detectable ctDNA in the pre-therapy plasma using NGS (p = 0.00075).
  • 80.8% of patients in the validation group had detectable ctDNA in the pre-therapy plasma.
  • A positive ctDNA result was associated with higher clinical tumor stage (56.2% vs. 28.6%, p = 0.027) and lymph node positivity (66.7% vs. 27.3%, p = 0.004).

Sources:

  • Performance Comparison of Droplet Digital PCR and Next-Generation Sequencing for Circulating Tumor DNA Detection in Non-Metastatic Rectal Cancer. Cancer Medicine, 2025,14(9):n/a-n/a.
  • Sigrid Juseliuksen Saatio
  • Suomen Laaketieteen Saatio
  • Jane Ja Aatos Erkon Saatio
  • Research Council of Finland
  • Relander Foundation
  • SyoPaSaatio

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