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EPISODE-III — Low-dose aspirin (100 mg/day, 3 yr) added to adjuvant chemotherapy, resected stage III colorectal cancer

Abstract: LBA3508 · Session: GI Cancer — Colorectal and Anal (Oral Abstract Session) · Presenter: Atsuo Takashima, MD, PhD (National Cancer Center Hospital, Tokyo)

At a glance

  • Sponsor: Japan Clinical Oncology Group (JCOG)
  • PI / presenter: Atsuo Takashima, MD, PhD — National Cancer Center Hospital, Tokyo
  • NCT ID: jRCTs031180009 (Japan registry; no NCT listed)
  • Phase: 3
  • Design: Randomized, double-blind, placebo-controlled; aspirin 100 mg/day vs placebo for 3 years on top of standard adjuvant chemotherapy (mFOLFOX6, CAPOX, or capecitabine)
  • N: 882 enrolled (876 in eligible-patient analysis population)
  • Primary endpoint(s): Disease-free survival (DFS)
  • Comparator: Placebo
  • Indication: Resected stage III colorectal cancer after curative resection
  • Line: Adjuvant

Headline result

Three years of adjuvant low-dose aspirin (100 mg/day) did not significantly improve DFS over placebo in resected stage III colorectal cancer. The 3-year DFS rate was 78.8% with aspirin vs 75.4% with placebo (HR 0.84, 95% CI 0.65–1.09; one-sided P = 0.099), missing the prespecified significance boundary despite a numerical 3.4-point absolute benefit. DFS events: 107 (aspirin) vs 124 (placebo). Relapse-free survival trended similarly (HR 0.87). Overall survival was immature and directionally null (HR 1.02, 95% CI 0.65–1.60), with the final OS analysis planned for 2028. Grade ≥3 aspirin-related adverse events occurred in <1% of patients.

Mechanism / class

Aspirin is a non-selective COX-1/COX-2 inhibitor. Its proposed anti-colorectal-cancer activity is linked to suppression of prostaglandin/PGE2-driven tumor signaling and, in particular, to PI3K/PIK3CA-pathway–altered tumors (the rationale behind the broader adjuvant-aspirin program). No oncology approval; widely used as antiplatelet/anti-inflammatory.

Discussant takeaway

Not reported in available sources.

Practice-changing?

No. The primary DFS endpoint was not met in an unselected stage III population, and OS is immature. Exploratory biomarker analyses (PI3K/PIK3CA) are ongoing and slated for a collaborative meta-analysis; any future role for adjuvant aspirin would likely hinge on a molecularly selected subgroup rather than all-comers.

  • Other ASCO 2026 trials: GI / colorectal — see trials index

Sources

  • ASCO Meeting Library (Abstract): https://www.asco.org/abstracts-presentations/ABSTRACT260625
  • CancerNetwork: https://www.cancernetwork.com/view/adjuvant-aspirin-misses-dfs-stage-iii-crc
  • OncoDaily: https://oncodaily.com/oncolibrary/gastrointestinal-oncology/episode-iii