PATIENTS with prostate cancer on active surveillance (AS) are increasingly interested in dietary strategies or supplements to help prevent the progression of their disease. A phase II, prospective randomised trial aimed to determine whether a high omega-3, low omega-6 fatty acid diet supplemented with fish oil capsules (D + FO) could reduce cellular proliferation, measured by the Ki-67 index, in prostate biopsies over a one-year period. This biomarker is closely associated with cancer progression, metastasis, and mortality.
The study enrolled 100 men diagnosed with grade group 1 or 2 prostate cancer who had chosen AS as their management strategy. Participants were randomly assigned to either the D + FO intervention group or a control group. Prostate biopsies were performed at the same sites at baseline and again at the one-year mark to assess changes in the Ki-67 index. The primary endpoint of the study was the difference in Ki-67 changes between the two groups over the trial period.
Results demonstrated that the Ki-67 index decreased in the D + FO group by approximately 15% from baseline to one year, reducing from 1.34% to 1.14%. In contrast, the control group showed an increase of approximately 24%, with values rising from 1.23% at baseline to 1.52% at one year. This difference between the groups was statistically significant (95% CI, 2%–52%; P=0.043). Secondary outcomes, including changes in grade group, tumour length, Decipher genomic score, and prostate-specific antigen levels, did not show significant differences between the groups. However, it is important to note that four patients in the D + FO group were withdrawn from the study due to adverse events related to fish oil supplementation.
The findings indicate that a high omega-3, low omega-6 fatty acid diet with fish oil supplementation can significantly reduce the Ki-67 index in men with prostate cancer on AS, suggesting a potential benefit in slowing disease progression. These results provide a strong rationale for advancing to phase III trials to confirm the efficacy and safety of this intervention in men on AS for prostate cancer.
Katie Wright, EMJ
Reference
Aronson WJ et al. High omega-3, low omega-6 diet with fish oil for men with prostate cancer on active surveillance: the CAPFISH-3 randomized clinical trial. J Clin Oncol. 2024;DOI:10.1200/JCO.24.00608.
