For many men with low-risk prostate cancer, active surveillance means living with cancer while delaying—or potentially avoiding—surgery or radiation therapy. It also leaves many patients asking what they can do beyond “wait and watch.”
Findings presented at the 2026 American Urological Association (AUA) Annual Meeting in Washington, DC, suggest that diet may be one answer, although not a replacement for careful monitoring.1 In a prospective cohort of 868 men with grade group 1 prostate cancer managed with active surveillance, greater adherence to a plant-based dietary pattern was associated with a lower risk of grade progression. In particular, the researchers found that consuming primarily a plant-based diet was associated with a significantly lower risk of progression to grade group 3 or worse disease during surveillance.1,2
Zhuo Tony Su, MD
Dr. Christian P. Pavlovich
The study was led by Zhuo Tony Su, MD, a former urology resident at the Brady Urological Institute at Johns Hopkins University School of Medicine at the time of this research, and currently a urologic oncology fellow at the National Cancer Institute, and senior author Dr. Christian P. Pavlovich, the Bernard L. Schwartz Distinguished Professor of Urologic Oncology at the Brady Urologic Institute. “For men with low-risk prostate cancer pursuing active surveillance, many are highly motivated to modify their diet and other lifestyle behaviors in order to reduce their risk of disease progression,” Dr. Su said. “However, there remains very limited evidence regarding whether any specific diet patterns may influence the risk of prostate cancer progression during surveillance.”
Why Diet Matters on Active Surveillance
Active surveillance has become the preferred initial management strategy for many men with low-risk prostate cancer, Dr. Pavlovich explained. That approach can help men delay or avoid the urinary, sexual, and other quality-of-life effects associated with prostate cancer treatment. But it can also be psychologically difficult for patients, especially those who want to take a more active role in their care.
To study whether dietary patterns were associated with progression, the investigators used prospective data from the Johns Hopkins prostate cancer active surveillance program, which Dr. Su described as one of the largest and longest-running prospective active surveillance cohorts in the world.
The analysis included men with grade group 1 prostate cancer who completed a validated food frequency questionnaire at the time they entered active surveillance. Using those self-reported baseline diet data, researchers calculated adherence scores for three dietary patterns: the alternate Mediterranean Diet, the Dietary Approaches to Stop Hypertension (DASH) diet, and a plant-based diet index. Unlike strictly vegetarian or vegan diets, a plant-based diet emphasizes plant foods—fruits, vegetables, beans, nuts, seeds, and whole grains—as the majority of caloric intake while limiting but not eliminating animal products and processed foods.
The study then looked at whether those diet scores were associated with upgrading to grade group 2 or higher disease and with “extreme upgrading” to grade group 3 or higher disease.
Study Findings
After a median follow-up of 7.9 years, 207 of the 868 men had their prostate cancer upgraded while on active surveillance. Of those, 61 progressed to grade group 3 or higher disease.2
Men with higher plant-based diet scores had a significantly lower risk of upgrading (P = .04) as well as progression to grade group 3 or higher disease (P = .046). Compared to men in the lowest quintile of plant-based diet scores, those in the top quintile had a 42% lower risk of upgrading (subdistribution hazard ratio [SHR] = 0.58, 95% confidence interval [CI] = 0.36–0.95), and a 57% lower risk of extreme upgrading to grade group 3 or worse disease (SHR = 0.43, 95% CI = 0.19–0.99).2
That grade group 3 finding is important, Dr. Pavlovich said, because men whose disease reaches grade group 3 or higher are generally advised to undergo definitive treatment, such as surgery or radiation therapy.
KEY POINTS
- In a prospective cohort of almost 900 men with grade group 1 prostate cancer managed with active surveillance, greater adherence to a plant-based diet pattern was associated with lower risk of grade progression.
- Plant-based diet adherence was significantly associated with lower risk of progression to grade group 3 or higher disease.
- Experts emphasized that diet should be discussed as part of active surveillance and survivorship counseling, not as a substitute for PSA monitoring, MRI when appropriate, and repeat biopsy.
Statistical significance was not observed for the Mediterranean or DASH diet patterns in the final analysis of the study. Unlike the plant-based diet pattern, the Mediterranean and DASH diet scores did not show a significant association with lower risk of either upgrading outcome. While an interim analysis suggested a statistically significant association for the Mediterranean diet with a reduced risk of grade progression,1 in the final analysis utilizing longer follow-up, this association was not statistically significant.2 Dr. Su emphasized that the Mediterranean and DASH diets should continue to be recommended to patients for their proven cardiovascular benefits. “These benefits are particularly meaningful in low-risk prostate cancer, where men are more likely to die from chronic diseases than from their prostate cancer,” he said.
Interpreting the Findings
Dr. Su emphasized that the study does not prove diet prevents prostate cancer progression.
“The most significant limitation is that our study was an observational study, not a randomized controlled trial, which remains the gold standard to establish cause-and-effect relationships,” he said. He also noted that the study was conducted at a single clinical center.
The study also relied on self-reported diet at the time of active surveillance enrollment. That means it may not capture diet changes over time, and it cannot rule out the possibility that men who follow plant-based diet patterns differ in other ways that could affect prostate cancer outcomes.
Still, Dr. Pavlovich said, “the findings may help inform evidence-based dietary recommendations for men seeking to mitigate their risk of disease progression.” He added that such recommendations could help some patients delay or even avoid definitive prostate cancer–directed treatment, such as prostatectomy or radiation therapy, as well as the associated effects on quality of life.
DISCLOSURE: Dr. Su and Dr. Pavlovich reported no conflicts of interest.
REFERENCES
1. Su ZT, Mamawala M, Landis PK, et al: Adherence to the Mediterranean and plant-based diets is associated with reduced risk of prostate cancer grade progression on active surveillance. 2026 American Urological Association Annual Meeting. Abstract 26-4923.
2. Su ZT, Mamawala M, Landis PK, et al: Dietary patterns, nutrients, and prostate cancer grade progression during active surveillance. 2026 (manuscript under review).
EXPERT POINT OF VIEW
Adam B. Weiner, MD, a urologic oncologist at Cedars-Sinai, said the findings stood out because the study focused on a clinically relevant active surveillance population.
“That includes patients with grade group 1 prostate cancer, on surveillance, followed prospectively, with grade progression as the endpoint,” Dr. Weiner said. “This was not just a study of prostate cancer incidence or general health outcomes.”
Adam B. Weiner, MD
The plant-based diet finding was especially interesting, he added, because it was associated with lower risk of progression to grade group 3 or higher disease. “This is important because grade group 3 or higher disease might require more intense treatment compared with progression to grade group 2,” Dr. Weiner said. He also pointed out that the DASH and Mediterranean diets was not associated with upgrading in this analysis, suggesting that not all “healthy” dietary patterns affect cancer biology the same.
At the same time, Dr. Weiner said clinicians should be careful not to overstate the findings. “I wouldn’t tell patients that a plant-forward diet has been ‘proven to prevent prostate cancer progression,’” he warned.
“For patients on active surveillance, I think it is reasonable to say that these diets are associated with a lower risk of upgrading in this study, but they should be viewed as simply a part of high-quality surveillance with PSA monitoring, MRI when appropriate, and repeat biopsy,” he said. “Diet changes are not a replacement for sticking with a standard surveillance plan.”
Dr. Weiner said the message he would give patients is, “We do not have definitive proof that diet will keep your prostate cancer from progressing, but the best available data suggest that a plant-forward diet may be favorable. At the very least, these diets have broader cardiovascular and metabolic benefits.”
Diet is one area in which clinicians can give practical, low-risk advice to patients who want to take an active role in reducing their risk, he said, but cautioned that diet counseling should be used to support patients, not burden them.
“We should not overpromise,” he said. “Diet counseling should empower patients, not make them feel that progression is somehow their fault if it does occur. Active surveillance still depends on tumor biology, sampling, imaging, pathology, and appropriate follow-up.”
DISCLOSURE: Dr. Weiner reported no conflicts of interest.
