A recent study highlights the link between diet and prostate cancer grade reclassification in men undergoing active surveillance.
In a groundbreaking cohort study involving 886 men with grade group (GG) 1 prostate cancer, researchers found that adherence to a healthier diet—specifically, one in line with the American dietary guidelines—could significantly reduce the risk of cancer grade reclassification. This study, conducted between 2005 and 2017, offers hope that diet modification could be an important factor in delaying or even preventing the progression of low-risk prostate cancer.
The men participating in the study were diagnosed with GG1 prostate cancer, a lower-risk form of the disease, and opted for active surveillance rather than immediate treatment. During this period, the risk of their cancer progressing to a more severe grade, particularly GG3, was monitored. Researchers assessed the dietary habits of the participants at the start of the study using a validated food frequency questionnaire. They then calculated two key dietary scores: the Healthy Eating Index (HEI) and the Dietary Inflammatory Index (DII).
The results were compelling. Men with higher baseline HEI scores—reflecting greater adherence to the American dietary guidelines, which emphasise fruits, vegetables, whole grains, and lean proteins—were less likely to experience cancer progression. Specifically, for every standard deviation increase in HEI score, there was a 15% reduction in the risk of the disease progressing to GG2 or greater, and a 28% reduction in the risk of extreme grade reclassification to GG3 or greater.
Moreover, energy-adjusted HEI (E-HEI) scores, which take caloric intake into account, also demonstrated a similar protective effect. Both HEI and E-HEI scores were inversely related to the likelihood of disease progression. In contrast, neither the DII nor the energy-adjusted DII scores, which estimate the inflammatory potential of a person’s diet, showed a significant association with prostate cancer grade reclassification.
The implications of this study are significant, as prostate cancer patients are increasingly seeking lifestyle changes that may reduce their risk of disease progression. The findings suggest that a diet rich in nutrient-dense foods and low in processed items could be a key factor in slowing the advance of prostate cancer, particularly for men with low-grade forms of the disease who are pursuing active surveillance.
The authors noted, “our results suggest that a higher-quality diet, indicated by higher baseline HEI and E-HEI scores, may be associated with a lower risk of extreme grade reclassification to GG3 or greater disease, a cancer state that mandates curative treatment.”
With a median follow-up period of 6.5 years, the study tracked a significant proportion of men who saw no progression in their cancer. At the 10-year mark, the cumulative incidence of grade reclassification was 33%, and extreme reclassification to GG3 or greater was 10%. Importantly, those with healthier diets were far less likely to see this aggressive progression.
While the study has limitations, including reliance on self-reported dietary habits and the predominantly white cohort, it provides a valuable insight into how diet may influence cancer outcomes. The researchers emphasize the need for further validation in larger, more diverse populations, but for now, the message is clear: for men with GG1 prostate cancer, a healthier diet may be a powerful tool in slowing the disease’s progression.
This new study underscores the importance of diet in the context of prostate cancer management. By closely following dietary guidelines, men with low-grade prostate cancer may improve their chances of avoiding more aggressive forms of the disease and delaying the need for curative treatment. As more research unfolds, dietary recommendations may become a key part of prostate cancer care strategies for men choosing active surveillance.
Paper: Su ZTMamawala MLandis PK, et al. Diet Quality, Dietary Inflammatory Potential, and Risk of Prostate Cancer Grade Reclassification. JAMA Oncol. Published online October 17, 2024. doi:10.1001/jamaoncol.2024.4406. Access online here.
