Diet appears to reduce growth rate in prostate cancer

Researchers report that a diet low in omega-6 and high in omega-3 fatty acids, combined with fish oil supplements has led to a reduced growth rate of prostate cancer cells in men with early-stage disease.

The findings were published on Dec 13, 2024 in the Journal of Clinical Oncology.

“This is an important step toward understanding how diet can potentially influence prostate cancer outcomes,” said author William Aronson, MD, Professor of Urology at the  David Gefffen School of Medicine at UCLA in Los Angeles, CA.  “Many men are interested in lifestyle changes, including diet, to help manage their cancer and prevent the progression of their disease. Our findings suggest that something as simple as adjusting your diet could potentially slow cancer growth and extend the time before more aggressive interventions are needed.”

The investigators in the CAPFISH-3 trial enrolled 100 men with low risk or favorable intermediate risk prostate cancer who had chosen active surveillance. Subjects were randomized to continue their normal diet (the control group) or to follow a low omega-6, high omega-3 diet, supplemented with fish oil, for one year (the intervention group).

Subjects in the intervention group received dietary personalized counseling by a dietician nutritionist. Those in the control group did not receive such counseling.

The researchers recorded changes in a biomarker called the Ki-67 index. Such changes indicate the speed at which cancer cells are multiplying, a key predictor of cancer progression, metastasis and survival.

The primary endpoint was the change in Ki-67 index from baseline to 1-year from same site biopsies, with comparison of findings between the study groups.

The investigators reported that the Ki-67 index decreased in the intervention group by approximately 15% from baseline to 1-year. It increased in the control group by approximately 24% from baseline to 1-year. This was a statistically significant difference in the change of Ki-67 index between the groups (p=0.043).

“This significant difference suggests that the dietary changes may help slow cancer growth, potentially delaying or even preventing the need for more aggressive treatments,” said Aronson, who is also the Chief of urologic oncology at the West Los Angeles Veterans Affairs Medical Center and a member of the UCLA Health Jonsson Comprehensive Cancer Center.

The investigators note that more research is needed to confirm the long-term benefits of omega-3 fatty acids and lowering omega-6 in managing prostate cancer.