Hull, Mark A.

Marine omega‐3 polyunsaturated fatty acids (MO3PUFAs) have anticancer properties and may improve colon cancer survival. However, it remains unknown whether the benefit differs by tumor molecular subtype. We examined data from a phase III randomized trial of FOLFOX or FOLFOX + cetuximab among 1,735 stage III colon cancer patients who completed a dietary questionnaire at enrollment. Multivariable hazard ratios and 95% confidence intervals (CIs) were calculated for the association between MO3PUFA and disease‐free survival (DFS) and overall survival according toKRASandBRAFV600Emutations and DNA mismatch repair (MMR) status. Higher MO3PUFA intake was associated with improved 3‐year DFS forKRASwild‐type tumors (77%vs. 73%; HR: 0.84; 95% CI: 0.67–1.05) but notKRAS‐mutant tumors (64%vs. 70%; HR: 1.30; 95% CI: 0.97–1.73;Pinteraction= 0.02). Similar heterogeneity was found by MMR (Pinteraction= 0.14): higher MO3PUFA was associated with better 3‐year DFS for tumors with deficient MMR (72%vs. 67%) but not proficient MMR (72%vs. 72%). No heterogeneity was found byBRAFV600Emutation. Similar findings were obtained for overall survival. In conclusion, we found a suggestive beneficial association between higher MO3PUFA intake and improved survival among stage III colon cancer patients with wild‐typeKRASand deficient MMR. Given the relatively small number of cases with tumor molecular assessments, further studies, preferably through pooled analyses of multiples cohorts, are needed to validate our findings.