Low serum magnesium concentration is associated with the presence of viable hepatocellular carcinoma tissue in cirrhotic patients.

This study aimed to ascertain, for the first time, whether serum magnesium (Mg) concentration is affected by the presence of hepatocellular carcinoma (HCC). We retrospectively enrolled consecutive cirrhotic patients with a diagnosis of HCC (n = 130) or without subsequent evidence of HCC during surveillance (n = 161). Serum levels of Mg were significantly (P < 0.001) lower in patients with HCC than in those without (median [interquartile range]: 1.80 [1.62-1.90] mg/dl vs. 1.90 [1.72-2.08] mg/dl). On multivariate logistic regression, low serum Mg was associated with the presence of HCC (OR 0.047, 95% CI 0.015-0.164; P < 0.0001), independently from factors that can influence magnesaemia and HCC development. In a subset of 94 patients with HCC, a linear mixed effects model adjusted for confounders showed that serum Mg at diagnosis of HCC was lower than before diagnosis of the tumor (β = 0.117, 95% CI 0.039-0.194, P = 0.0035) and compared to after locoregional treatment of HCC (β = 0.079, 95% CI 0.010-0.149, P = 0.0259), with two thirds of patients experiencing these changes of serum Mg over time. We hypothesize that most HCCs, like other cancers, may be avid for Mg and behave like a Mg trap, disturbing the body's Mg balance and resulting in lowering of serum Mg levels.