Aspirin as an Adjuvant Therapy in Colorectal Cancer

Aspirin use reduces the risk of colorectal cancer, and retrospective studies have suggested that aspirin use after surgery may reduce recurrence risk, particularly in patients with somatic PIK3CA mutations. Now, investigators report results from a double-blind, randomized, placebo-controlled trial of aspirin use (160 mg daily for 3 years) in 625 patients with resected stage I–III colorectal cancers harboring such mutations. Half had PIK3CA mutations in exon 9 or 20 (group A), and half had other moderate- to high-impact somatic variants in PIK3CA, PIK3R1, or PTEN (group B). About one third had rectal cancer, half had right-sided primaries, and a quarter had tumors with high microsatellite instability.