New research showed the association between high intake of marine ω-3 polyunsaturated fatty acids (ω-3 PUFAs) and survival of patients with colorectal cancer (CRC). Increasing consumption of marine ω-3 PUFAs after diagnosis may confer additional benefits to patients with CRC.

Despite appreciable advances in treatment, colorectal cancer (CRC) still represents the third leading cause of cancer death in the USA. The experimental evidence supports an antineoplastic activity of marine ω-3 PUFAs; including eicosapentaenoic acid, docosahexaenoic acid and docosapentaenoic acid. However, the influence of ω-3 PUFAs on (CRC) survival was not clear.

In laboratory studies, it has been shown that marine ω-3 PUFAs suppress tumour growth and angiogenesis, possibly through modulation of prostaglandin-endoperoxide synthase (PTGS) activity. Supplementation of ω-3 PUFAs has been reported to enhance antitumor effects of chemotherapeutic agents in CRC.

Substantial evidence also suggests that ω-3 PUFAs can inhibit cancer-related cachexia by improving food intake, delaying the onset of anorexia and preventing body weight loss. Within the Nurses' Health Study and Health Professionals Follow-up Study, the researchers prospectively studied CRC-specific and overall mortality in a cohort of 1659 patients with CRC according to the intake of marine ω-3 PUFAs and its change after diagnosis.

Higher intake of marine ω-3 PUFAs after CRC diagnosis was associated with lower risk of CRC-specific mortality (p for trend=0.03). Compared with patients who consumed <0.10 g/day of marine ω-3 PUFAs, those consuming at least 0.30 g/day had an adjusted HR for CRC-specific mortality of 0.59 (95% CI 0.35 to 1.01).

Patients who increased their marine ω-3 PUFA intake by at least 0.15 g/day after diagnosis had an HR of 0.30 (95% CI 0.14 to 0.64, p for trend <0.001) for CRC deaths, compared with those who did not change or changed their intake by <0.02 g/day. No association was found between post-diagnostic marine ω-3 PUFA intake and all-cause mortality (p for trend=0.47).

Higher marine ω-3 PUFAs intake after CRC diagnosis lowers the risk of CRC-specific mortality. Patients with CRC who increased their intake from their levels before diagnosis experienced a considerable reduction in CRC-specific mortality and a moderate reduction in all-cause mortality. The study findings provide novel evidence for the potential benefit of increasing marine ω-3 PUFA consumption among patients with CRC.