A recent investigation led by investigators from the UCLA Health Jonsson Comprehensive Cancer Center provides fresh evidence that altering one’s diet may slow down cancer cell growth in patients undergoing active surveillance—a strategy that entails regular observation of cancer without immediate treatment.
The results, published in the Journal of Clinical Oncology, reveal that a diet low in omega-6 alongside a high intake of omega-3 fatty acids, supplemented with fish oil, significantly decreased the growth rates of prostate cancer cells in men diagnosed with early-stage disease.
“This represents a crucial advancement in understanding how dietary habits could possibly affect prostate cancer outcomes,” stated Dr. William Aronson, a Professor of Urology at the David Geffen School of Medicine at UCLA and the lead author of the study. “Many men seeking to manage their cancer are keen on making lifestyle changes, especially in their diet, to prevent their disease from worsening. Our study indicates that something as straightforward as modifying your diet might help slow cancer development and prolong the need for more invasive interventions.”
Many men diagnosed with low-risk prostate cancer opt for active surveillance rather than immediate treatment. However, about 50% of these men require additional therapies such as surgery or radiation within five years. Consequently, there is a growing interest in adopting dietary changes or taking supplements as a way to postpone treatment. Unfortunately, specific dietary recommendations for this purpose have not yet been established. While other clinical trials have focused on increasing vegetable consumption and promoting healthier eating patterns, none have shown a significant effect on hindering cancer progression.
To explore the impact of diet and supplements on managing prostate cancer, the UCLA research group conducted the CAPFISH-3 trial. This prospective clinical trial involved 100 men with low-risk or favorable intermediate-risk prostate cancer who chose active surveillance. Participants were randomly selected to either maintain their regular diet or switch to a low omega-6, high omega-3 diet, supplemented with fish oil, for a period of one year.
Those in the intervention group received tailored dietary advice from a registered dietitian nutritionist, either in-person, via telehealth, or over the phone. They were advised to opt for healthier, lower-fat alternatives to high-calorie foods (such as using olive oil or a lemon-vinegar mixture for salad dressing) and to minimize intake of foods high in omega-6 (like chips, cookies, mayonnaise, and other fried or processed items). The objective was to achieve a better balance of omega-6 and omega-3 fats and empower participants to manage their dietary modifications. Additionally, they were provided with fish oil capsules for added omega-3s. In contrast, the control group did not receive any dietary guidance or fish oil supplements.
The researchers monitored changes in a biomarker known as the Ki-67 index, which indicates the rate of cancer cell multiplication—an essential factor for predicting cancer progression, metastasis, and overall survival.
Biopsies from the same locations were conducted at the start and after one year, utilizing an imaging fusion device that aids in tracking and locating cancer sites.
The findings demonstrated that the group following the low omega-6, omega-3 rich diet with fish oil had a 15% decrease in their Ki-67 index, while the control group displayed a 24% increase.
“This notable difference implies that dietary adjustments could play a role in decelerating cancer growth, potentially postponing or even averting the need for more aggressive treatments,” remarked Aronson, who also serves as the Chief of Urologic Oncology at the West Los Angeles Veterans Affairs Medical Center and is a member of the UCLA Health Jonsson Comprehensive Cancer Center.
Despite the encouraging results, the researchers did not observe variations in other cancer growth indicators like the Gleason grade, which are typically utilized to monitor prostate cancer progression.
The authors emphasize the need for additional research to validate the long-term advantages of omega-3 fatty acids and the reduction of omega-6 in prostate cancer management. These findings promote the necessity for further extensive trials to investigate the prolonged effects of dietary shifts on cancer progression, treatment results, and survival rates in men undergoing active surveillance.
The senior author of the study is Dr. Susanne Henning, an adjunct professor emerita and former director of the nutritional biomarker laboratory at UCLA’s Center for Human Nutrition. Additional UCLA co-authors include Tristan Grogan, Dr. Pei Liang, Patricia Jardack, Amana Liddell, Claudia Perez, Dr. David Elashoff, Dr. Jonathan Said, and Dr. Leonard Marks.
This study received partial funding from the National Cancer Institute, the UCLA Health Jonsson Comprehensive Cancer Center, Howard B. Klein, and the Seafood Industry Research Fund.
