Background: Cardiovascular disease and cancer are major public health concerns worldwide. Despite the beneficial effects of the anthracycline based anti-cancer agent Doxorubicin (DOX) in treating women with breast cancer, cardiotoxicity is a major challenge. Although recent basic science studies have demonstrated the cardioprotective role of flaxseed (FLX) in the prevention of DOX mediated cardiotoxicity, little is known about the effects of this nutraceutical in the clinical setting. The aim of the “Can flaxseed “milk” prevent broken hearts in women with breast cancer?” (CANFLAX) study is to investigate whether consumption of FLX “milk” can prevent heart failure in women with breast cancer treated with anthracyclines.

Methods: In this double-blind prospective randomized controlled clinical trial, prior to initiation of DOX-based chemotherapy, women with breast cancer were randomized to either placebo oat fiber “milk” or FLX “milk” for a total of 4 months. Baseline demographic data, echocardiography, and blood work were measured at baseline, 4-months, 6-months and 12-months post-intervention. Baseline demographic data was collected using CancerCare Manitoba’s medical record database (ARIA) MedOncology Manager. Serial transthoracic echocardiography (TTE) was conducted to assess cardiovascular systolic and diastolic function, including strain parameters.

Results: A total of 18 women with early-stage breast cancer (EBC) have been enrolled between September 2021 to December 2022 in the CANFLAX study. Out of the 18 participants, 15 women (mean age 4710 years) with average body mass index (BMI) of 295.2 kg/m2 have completed both the baseline and 4 month follow-up. Out of this cohort of 15 women, a total of 6 were randomized to group A and 9 were randomized to group B; the identity of the 2 study products is double-blinded. The prevalence of underlying cardiovascular risk factors was low in both groups.

In total, 2 (13%) participants had hypertension, 1 (6%) participant had hyperlipidemia, diabetes, and past smoking history, and 5 (33%) participants had a family history of premature coronary artery disease (CAD). The overall “milk” adherence was rate was approximately 70% during the 16 week “milk” intake period. There were no significant differences between the two groups in the measured cardiovascular morphological or functional parameters. The baseline left ventricular ejection fraction (LVEF) values were 683% and 694%, for groups A and B, respectively. At 4 months follow up, mean LVEF was 69±3% and 70±2% in group-A and group-B, respectively (p = NS). Additionally, at baseline, the mean global longitudinal strain (GLS) was -18.2±0.3% in group-A and -18.4±0.3% in group B (p=NS). At 4 months follow up, the GLS was lower in Group A at -14.9±0.2% in comparison to a GLS of -18.1±0.2% for Group B (p<0.05).

Conclusion: The findings of the ongoing CANFLAX study highlight the feasibility of consuming either oat fibre “milk” or flax “milk” in women treated with anthracyclines for breast cancer. Whether the prophylactic administration of FLX “milk” is cardioprotective in the setting of anthracycline-mediated cardiotoxicity in the breast cancer setting remains to be determined.