Adjuvant aspirin may do more harm than good in patients with CRC liver metastases

Use of aspirin after curative-intent treatment of colorectal cancer (CRC) liver metastases does not appear to improve disease-free survival and is even associated with reduced overall survival and more serious adverse events (AEs), according to the phase III ASAC trial

ASAC included 428 patients (mean age 62.2 years, 64 percent male) who had undergone curative-intent treatment for CRC liver metastases. These patients were randomly assigned to receive aspirin 160 mg (n=217) or matching placebo (n=211), taken daily for up to 3 years or until recurrence, death, or treatment discontinuation.

The primary outcome of disease-free survival did not significantly differ between the aspirin and placebo groups (138 vs 131 events; hazard ratio [HR] for recurrence or death, 1.08, 95.44 percent confidence interval [CI], 0.85–1.38; p=0.58). Median disease-free survival was 1.13 years with aspirin vs 1.4 years with placebo.

Overall survival rate at 36 months was 76 percent with aspirin vs 85 percent with placebo (HR for death, 1.64, 95 percent CI, 1.01–2.65; p=0.045). Time to recurrence was similar between the two groups (adjusted cause-specific HR, 1.06, 95 percent CI, 0.83–1.35; p=0.64).

As for safety, serious AEs occurred in 8 percent of patients in the aspirin group and 2 percent in the placebo group. Common clinically relevant AEs and serious AEs in the aspirin group were myocardial infarction, epistaxis, duodenal ulcer, and cerebral haemorrhage. No treatment-related deaths occurred.