Abstract
Objective: The aim of this systematic review was to compare the impact of various dietary patterns on cancer mortality, recurrence, remission, quality of life, and prostate-specific antigen (PSA) in non-metastatic prostate cancer patients. Methods: Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and Scopus databaseswere searched from inception to March 2024. Dietary interventions or observational studies investigating dietary patterns in men with non-metastatic prostate cancer with at least one primary outcome related to mortality, recurrence, remission, quality of life or PSA/PSA doubling time were included. Two independent reviewers conducted article selection, data extraction, and quality assessment. Results: Sixteen eligible articles were included. Adherence to a Mediterranean dietary pattern was linked to lower overall mortality and increased quality of life and adherence to a Prudent diet was associated with both lower overall and cancer-specific mortality risk. A plant-based dietary pattern is associated with increased quality of life. Contrastingly, a Western diet was associated with a higher cancer-specific mortality and overall mortality and high-inflammatory, hyperinsulinaemic, and insulin-resistant diets with increased recurrence. Conclusions: Despite the heterogeneity and inconsistencies of PCa literature, there is fair evidence that suggests unprocessed foods with healthier dietary patterns of Mediterranean and prudent diets confer a beneficial effect on overall and cancer-specific mortality, recurrence, and quality of life whereas, a more Western and unhealthier diet generates the opposite. The increased risk of bias prevents conclusive interpretation of these results and, hence, detracts from its clinical implementation. Future research should focus on increasing sample sizes and robustness and standardisation in study design.