Weight gain or loss after diagnosis and survival outcomes in prostate cancer: a meta-analysis.

[BACKGROUND] The relationship between weight changes and survival outcomes in patients with prostate cancer remains inconclusive. This meta-analysis aims to investigate the association between post-diagnosis weight changes and survival outcomes in patients with prostate cancer.

[METHODS] We systematically searched for articles indexed in the PubMed, Web of Science, and Embase databases until March 22, 2025. Longitudinal observational studies that examined the association between post-diagnosis weight change and prostate cancer-specific mortality (PCSM) or all-cause mortality among patients with prostate cancer were eligible for inclusion in this analysis. Weight gain and weight loss were defined as either a percentage change from baseline body weight at diagnosis or treatment start, or as an absolute change in kilograms over a specified period. Despite variations in the measured statistical heterogeneity, we employed a random-effects model for all meta-analyses to account for inherent differences in the definitions of weight change.

[RESULTS] Six studies involving 12,269 patients were included in the meta-analysis. When compared to a reference stable weight, post-diagnosis weight gain was associated with an increased risk of all-cause mortality (hazard ratio [HR] 1.23; 95% confidence interval [CI] 1.07–1.42) and PCSM (HR 1.64; 95% CI 1.30–2.07). Conversely, weight loss was linked to an increased risk of all-cause mortality (HR 1.54; 95% CI 1.20–1.97), while no significant association was found between weight loss and PCSM (HR 1.30; 95% CI 0.76–2.22). Begg’s and Egger’s tests indicated no evidence of publication bias. Subgroup analyses revealed that both weight loss (HR 1.38; 95% CI 1.07–1.79) and weight gain (HR 1.25; 95% CI 1.08–1.46) were significantly associated with all-cause mortality when the analysis was restricted to patients with non-metastatic or localized prostate cancer.

[CONCLUSIONS] Post-diagnosis weight gain is significantly associated with both all-cause mortality and PCSM in patients with prostate cancer, particularly in those with non-metastatic or localized disease. In contrast, weight loss is primarily linked to an increased risk of all-cause mortality but not to PCSM. However, the observational nature of our data limits our ability to draw definitive conclusions regarding causality.

[SUPPLEMENTARY INFORMATION] The online version contains supplementary material available at 10.1186/s12885-025-14704-w.