The effects of EPA and DHA enriched fish oil on nutritional and immunological markers of treatment naïve breast cancer patients: a randomized double-blind controlled trial

Randomized, double-blind, placebo-controlled trial in treatment-naïve female breast cancer patients aged 18–70 years with BI-RADS 4C or higher scheduled for surgery; conducted at University Hospital of Brasilia and Base Hospital of the Federal District, Brazil. Inclusion: treatment-naïve, 18–70 years; Exclusion: metastatic or recurrent disease, comorbidity preventing fish oil use, pacemaker users, edema. 45 randomized; 37 completed (FG n=18; PG n=19).

Fish oil concentrate, 2 g/day (two 1 g capsules), containing 1.8 g total n-3 fatty acids, for 30 days; taken at lunch and dinner.

After 30 days, plasma EPA and DHA increased in the fish oil group. CD4+ T lymphocytes and hsCRP were maintained in the fish oil group, while the placebo group showed a decrease in CD4+ T cells and an increase in hsCRP. No changes were observed in proinflammatory cytokines or PGE2 in either group. The n-6/n-3 fatty acid ratio decreased in the fish oil group. Authors interpret this as a potential beneficial effect of EPA/DHA on immune function and inflammatory status in newly diagnosed, treatment-naïve breast cancer patients prior to surgery; results suggest a favorable immunomodulatory effect but are restricted by small sample size and short duration.

Small sample size (37 completers); short duration (30 days); single-country/center study; dropouts and some changes to neoadjuvant treatment reduced power; potential partial unblinding due to placebo odor; preoperative context may limit generalizability.