Serum Levels of Heavy Metals in Patients with Prostate Cancer: A Systematic Review and Meta-analysis.

Prostate cancer (PC) is a common malignancy among men globally. Although genetic, hormonal, and environmental factors contribute to its development, the role of heavy metals remains unclear. This study evaluated serum levels of arsenic, cadmium, lead, mercury, and nickel in PC patients compared to healthy controls. An extensive search of PubMed, Embase, Scopus, and Google Scholar identified relevant studies published up to December 2023. Studies reporting the mean and standard deviation of serum heavy metal levels in PC patients and controls were included. Random-effects models were used to estimate mean differences (MD) or standardized mean differences (SMD) with 95% confidence intervals (CIs). Heterogeneity was evaluated based on I index, and publication bias was examined using funnel plots. Seven studies involving 691 participants were included. No significant difference was found in serum levels of arsenic between PC patients and controls (MD: 0.04, 95% CI: [-0.15, 0.23]; p = 0.68). Cadmium (SMD: 0.93, 95% CI: [-0.06, 1.93]; p = 0.07) and lead (SMD: 0.65, 95% CI: [-0.22, 1.52]; p = 0.14) were higher in PC patients but not statistically significant. Mercury levels also showed no substantial difference (MD: 0.22, 95% CI: [-0.27, 0.70]; p = 0.38). However, serum nickel levels were significantly higher in PC patients (SMD: 0.62, 95% CI: [0.07, 1.16]; p = 0.03). The study demonstrated a substantial increase in serum concentration of nickel in PC patients compared to controls, indicating a potential role of nickel in PC pathogenesis. Although other heavy metals showed elevated levels in PC patients, these differences were not statistically significant. Further research is needed to explore nickel as a potential biomarker for early PC detection.