In a single-institution phase II trial (CAPFISH-3) reported in the Journal of Clinical Oncology, Aronson et al found that men with prostate cancer on active surveillance had a significantly reduced Ki67 index on a high omega-3, low omega-6 fatty acid diet with fish oil capsules vs no dietary intervention.
Study Details
In the open-label trial, conducted from December 2014 to September 2022, 91 evaluable patients from the University of California Los Angeles with grade group 1 or 2 cancer who elected active surveillance were randomly assigned to the dietary intervention (n = 44) or control group (no dietary intervention (n = 47). Same-site prostate biopsies were obtained at baseline and at 1 year; the primary outcome measure was change in Ki67 index from baseline to 1 year from same-site biopsies compared between the two groups.
Key Findings
The Ki67 index decreased in the intervention group by approximately 15%, from 1.34% at baseline to 1.14% at 1 year, and increased in the control group by approximately 24%, from 1.23% at baseline to 1.52% at 1 year. The outcomes yielded a statistically significant 31% differential reduction (95% confidence interval [CI] = 2%–52%, P = .043) favoring the intervention group.
No significant differences between groups were observed for grade group, tumor length, Decipher genomic score, or prostate-specific antigen level.
A total of four patients in the intervention group discontinued treatment because of adverse events related to fish oil capsules.
The investigators concluded: “A high omega-3, low omega-6 diet with [fish oil] for 1 year resulted in a significant reduction in Ki67 index, a biomarker for prostate cancer progression, metastasis, and death. These findings support future phase III trials incorporating this intervention in men on active surveillance.”
William J. Aronson, MD, of the Department of Urology, David Geffen School of Medicine, University of California Los Angeles, is the corresponding author of the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit ascopubs.org.
