In stage III colon cancer, circulating tumor DNA shows prognostic promise

  • Tie J & al.
  • JAMA Oncol
  • 17 Oct 2019

  • curated by Jim Kling
  • Univadis Clinical Summaries
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Takeaway

  • Detectable levels of circulating tumor DNA (ctDNA) following surgery and adjuvant chemotherapy are associated with worse recurrence-free survival in stage III colon cancer.

Why this matters

  • ctDNA may predict patient response to treatment after surgery and adjuvant chemotherapy.
  • ctDNA levels after adjuvant chemotherapy may be the most relevant predictor, according to an accompanying editorial.

Study design

  • Multicenter cohort study (n=96).
  • Tumor DNA was detected by sequencing 15 genes for mutations commonly associated with cancer.
  • Funding: Victorian Cancer Agency; NIH; Virginia and D. K. Ludwig Fund for Cancer Research; John Templeton Foundation.

Key results

  • Median follow-up, 28.9 months.
  • All 96 patients had at least 1 somatic mutation in the primary tumor among the 15 genes tested.
  • Following surgery, 21% of patients had detectable ctDNA, and this was associated with worse recurrence-free survival (HR, 3.8; P<.001 this remained significant after adjustment for clinicopathologic risk factors p>
  • Following adjuvant chemotherapy, 17% had detectable ctDNA, and this was associated with a worse 3-year recurrence-free interval (30% vs 77%; HR, 6.8; P<.001>

Limitations

  • No validation cohort.
  • Modest sample size.