Table 3.
Association between post-diagnostic marine ω-3 polyunsaturated fatty acid (MO3PUFA) intake and disease-free survival and overall survival according to tumor subsite and molecular markers among patients with stage III colon cancer*
| Disease-free survival (DFS) |
Overall survival (OS) |
|||||||
|---|---|---|---|---|---|---|---|---|
| No. of events/patients | 3-year survival (%) | HR (95% CI) † | P for interaction‡ | No. of events/patients | 5-year survival (%) | HR (95% CI) † | P for interaction‡ | |
| KRAS mutation | ||||||||
| Mutant | ||||||||
| Low intake | 91/282 | 70 | 1 (reference) | 0.02 | 79/282 | 78 | 1 (reference) | 0.04 |
| High intake | 123/301 | 64 | 1.30 (0.97–1.73) | 103/301 | 72 | 1.26 (0.92–1.71) | ||
| Wildtype | ||||||||
| Low intake | 181/553 | 73 | 1 (reference) | 154/553 | 77 | 1 (reference) | ||
| High intake | 146/522 | 77 | 0.84 (0.67–1.05) | 122/522 | 84 | 0.85 (0.67–1.09) | ||
| MMR status | ||||||||
| pMMR | ||||||||
| Low intake | 231/726 | 72 | 1 (reference) | 0.14 | 200/726 | 78 | 1 (reference) | 0.47 |
| High intake | 243/727 | 72 | 1.08 (0.89–1.30) | 196/727 | 80 | 1.03 (0.84–1.27) | ||
| dMMR | ||||||||
| Low intake | 40/105 | 67 | 1 (reference) | 35/105 | 68 | 1 (reference) | ||
| High intake | 31/106 | 72 | 0.69 (0.41-1.16) | 31/106 | 75 | 0.78 (0.46–1.34) | ||
| BRAF mutation | ||||||||
| Mutant | ||||||||
| Low intake | 44/117 | 68 | 1 (reference) | 0.73 | 46/117 | 64 | 1 (reference) | 0.90 |
| High intake | 42/112 | 70 | 1.01 (0.64–1.58) | 42/112 | 68 | 1.00 (0.64–1.57) | ||
| Wildtype | ||||||||
| Low intake | 219/690 | 73 | 1 (reference) | 179/690 | 80 | 1 (reference) | ||
| High intake | 222/693 | 73 | 1.02 (0.84–1.23) | 179/693 | 81 | 1.04 (0.84–1.29) | ||
| MMR/BRAF status | ||||||||
| pMMR/Mutant | ||||||||
| Low intake | 21/64 | 70 | 1 (reference) | 0.12 | 22/64 | 68 | 1 (reference) | 0.07 |
| High intake | 29/60 | 63 | 1.74 (0.90–3.35) | 29/60 | 60 | 1.65(0.87–3.16) | ||
| dMMR/Mutant | ||||||||
| Low intake | 23/51 | 63 | 1 (reference) | 24/51 | 55 | 1 (reference) | ||
| High intake | 13/50 | 76 | 0.47 (0.20–1.12) | 13/50 | 75 | 0.42(0.17–1.02) | ||
| pMMR/Wildtype | ||||||||
| Low intake | 201/629 | 72 | 1 (reference) | 168/629 | 79 | 1 (reference) | ||
| High intake | 204/633 | 73 | 1.02 (0.84–1.25) | 161/633 | 81 | 1.01(0.81–1.27) | ||
| dMMR/Wildtype | ||||||||
| Low intake | 14/48 | 72 | 1 (reference) | 9/48 | 80 | 1 (reference) | ||
| High intake | 17/54 | 68 | 0.59 (0.25–1.38) | 17/54 | 74 | 0.93(0.34–2.58) | ||
Abbreviation: dMMR, deficient mismatch repair; CI, confidence interval; HR, hazard ratio; pMMR, proficient mismatch repair.
Only patients who had available data on stratified variables (i.e., tumor subsite and molecular markers) were included in the analysis. Low intake was defined as below the median in each sex, and high intake as equal to or above the median intake. The median intake of MO3PUFA was 0.05 g/day in women and 0.06 g/day in men.
Multivariable HRs (95% CIs) were derived from model 2 described in Table 2.
Wald test was used to calculate the p value for the product term between the stratified variable and MO3PUFA intake (both binary) except for the analysis by the joint MMR/BRAF status, for which likelihood ratio test with 3 degrees of freedom was used to compare the models with and without the product terms between MO3PUFA intake and MMR/BRAF status (4 categories).