Trace element concentration in metastatic liver disease – A systematic review

BackgroundThere are conflicting reports about the levels of trace elements in secondary liver cancers. This review summarises the evidence associating secondary liver tumours with trace elements.MethodsMEDLINE, EMBASE and CENTRAL databases were searched for the period up to January 2006 using a formal search strategy. Various inclusion and exclusion criteria were applied to select the articles for inclusion. Data extraction was performed using a custom designed data extraction form.ResultsA total of 6917 references were identified. About 1359 duplicates were excluded using EndNote. About 5529 clearly irrelevant references were excluded through reading titles and abstracts. Of these 24 references were excluded by applying the exclusion criteria. Five studies including 239 patients and measuring iron content (2), copper content (4) and zinc (3) qualified for the review. Both studies on iron, three studies on copper and all the studies on zinc used quantitative methods to determine mineral content. A meta-analysis was performed using the random effects model.ConclusionCopper and zinc content are lower in secondary liver cancer compared to livers from healthy patients. Iron, copper and zinc content are lower in liver secondaries compared to the normal tissues surrounding the secondaries. Reasons and implications for the trace element alterations should be further investigated.