The SAKK 41/13 trial provides the first randomized evidence that adjuvant aspirin 100mg daily may improve disease-free survival in patients with resected PIK3CA-mutant colon cancer, showing a clinically meaningful 43% reduction in disease recurrence risk, though statistical significance was not achieved due to premature trial closure.
Study Design & Population
- Study Type: Phase III, prospective, randomized, placebo-controlled, double-blind, multicenter trial
- Population: 112 patients with resected stage II-III colon cancer harboring activating PIK3CA mutations
- Demographics: Median age 66 years, 42.9% female
- Intervention: Aspirin 100mg daily vs placebo for 3 years (2:1 randomization)
- Follow-up: Median 4 years
Key Findings
- Primary Endpoint (DFS): HR 0.57 (90% CI 0.27-1.22, p=0.11) favoring aspirin
- 5-year DFS rates: 86.5% aspirin arm vs 72.9% placebo arm
- Time to Recurrence: HR 0.49 (90% CI 0.21-1.19, p=0.089) favoring aspirin
- Safety: No aspirin-related serious adverse events reported
- Screening: 1,040 patients screened to identify 112 with PIK3CA mutations
Clinical Implications
- Practice Consideration: Individual risk-benefit assessment warranted for adjuvant aspirin in PIK3CA-mutant colon cancer patients
- Patient Selection: Results apply specifically to stage II-III colon cancer with confirmed PIK3CA mutations
- Treatment Duration: 3-year adjuvant treatment period demonstrated safety profile
- Biomarker Strategy: Reinforces importance of PIK3CA mutation testing in colon cancer
Limitations
- Premature Closure: Trial terminated early due to financial constraints, limiting statistical power
- Sample Size: Only 112 patients enrolled from 1,040 screened (10.8% mutation rate)
- Statistical Significance: Primary endpoint did not reach statistical significance despite clinically relevant effect size
- Generalizability: Results specific to PIK3CA-mutant subset, not applicable to wild-type tumors
Source: https://aacrjournals.org/clincancerres/article-abstract/31/15/3142/763800/Adjuvant-Aspirin-Treatment-in-PIK3CA-Mutated-Colon
