Stage II colon cancer: mismatch repair status may aid in adjuvant chemo decision

  • Gkekas I & al.
  • J Surg Oncol
  • 11 Dec 2019

  • curated by Jim Kling
  • Univadis Clinical Summaries
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Takeaway

  • Adjuvant chemotherapy is associated with improved outcomes in proficient mismatch repair (pMMR) status stage II colon cancer tumors, but not in defective mismatch repair (dMMR) tumors.

Why this matters

  • Adjuvant chemotherapy is generally reserved for "high-risk" patients with stage II colon cancer, but no firm data show that the markers for this diagnosis are reliably predictive.

Study design

  • Retrospective, multicenter study (N=451; dMMR, 92; pMMR, 359).
  • Funding: None disclosed.

Key results

  • Median follow-up, 73 (79.1 pMMR vs 67.6 dMMR; P=.004) months.
  • Adjuvant treatment was not associated with a survival benefit in patients with dMMR tumors (HR, 1.05; P=.897).
  • In a multivariable model, adjuvant treatment was associated with better OS in patients with pMMR tumors (HR, 0.42; P=.007).
  • Among patients who relapsed, postrelapse survival was not significantly different with respect to postoperative management in the dMMR group, but pMMR patients who were treated with adjuvant chemotherapy had a longer postrelapse survival (HR, 0.55; P=.033).

Limitations

  • Retrospective analysis.