Plant-based diet may reduce risk of prostate cancer progression

Findings from a recent study published in JAMA Network Open show that a higher intake of plant-based foods following a diagnosis of prostate cancer is associated with a reduced risk of disease progression.¹

"Greater consumption of plant-based food after a prostate cancer diagnosis has also recently been associated with better quality of life, including sexual function, urinary function, and vitality, so it’s a win-win on both levels,” says Stacey A. Kenfield, ScD.

“These results could guide people to make better, more healthful choices across their whole diet, rather than adding or removing select foods,” said lead author Vivian N. Liu, MAS, formerly lead clinical research coordinator at the UCSF Osher Center for Integrative Health, in a news release on the findings.² “Progressing to advanced disease is one of many pivotal concerns among patients with prostate cancer, their family, caregivers, and physicians. This adds to numerous other health benefits associated with consuming a primarily plant-based diet, such as a reduction in diabetes, cardiovascular disease, and overall mortality.”

For the study, patients received a comprehensive diet and lifestyle questionnaire, which included a validated food frequency questionnaire (FFQ). The FFQ was used to calculate overall plant-based diet index (PDI) and healthful plant-based diet index (hPDI) scores.

The median time from diagnosis of prostate cancer to the completion of the FFQ was 31.3 months. At a median follow-up of 6.5 years following the FFQ, 190 progression events and 61 prostate cancer-specific mortality events were reported among the 2062 patients included in the study.

Patients who scored in the highest quintile of PDI scores had a 47% lower risk of prostate cancer progression compared with those in the lowest quintile (HR, 0.53; 95% CI, 0.37-0.74; P = .003).

There was no association observed between the highest and lowest hPDI scores and the risk of progression overall (HR, 0.81; 95% CI, 0.54-1.20; P = .34). However, the investigators noted that among those with Gleason grade 7 or higher disease at diagnosis (n = 680), those in the highest hPDI quintile had a 55% lower risk of progression compared with those in the lowest hPDI quintile (HR, 0.45; 95% CI, 0.25-0.81; P = .01). There was no association found between hPDI scores and progression among patients with Gleason grades less than 7.

The investigators also found no statistically significant associations between dietary index and the risk of prostate cancer-specific mortality.

“Making small changes in one’s diet each day is beneficial. Greater consumption of plant-based food after a prostate cancer diagnosis has also recently been associated with better quality of life, including sexual function, urinary function, and vitality, so it’s a win-win on both levels,” added senior author Stacey A. Kenfield, ScD, a UCSF professor of urology and the Helen Diller Family Chair in Population Science for Urologic Cancer, in the news release.²

Overall, the study included 2062 patients with biopsy-proven non-metastatic prostate cancer. The median age of patients was 65 years (IQR, 59-70). The study was conducted as a diet and lifestyle substudy within the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) study.

The primary outcome measure for the study was time to prostate cancer progression, which included biochemical recurrence, secondary treatment, bone metastases, or death due to prostate cancer. The secondary outcome measure was prostate cancer-specific mortality.

The authors concluded,¹ “The findings of this cohort study suggest that plant-based dietary patterns may be inversely associated with risk of prostate cancer progression, although future research and replication of our findings is needed. These data are consistent with prior research demonstrating the importance of dietary factors in overall health and well-being.”

References

1. Liu VN, Blarigan ELV, Zhang L, et al. Plant-based diets and disease progression in men with prostate cancer. JAMA Netw Open. 2024;7(5):e249053. doi:10.1001/jamanetworkopen.2024.9053

2. Prostate cancer study: More health benefits from plant-based diet. News release. University of California, San Francisco. May 13, 2024. Accessed May 14, 2024. https://www.ucsf.edu/news/2024/05/427571/prostate-cancer-study-more-health-benefits-plant-based-diet