Does sarcoma occur in man after intramuscular iron?

Several factors influence the induction of sarcomas at the site of iron carbohydrate complex injection in high dosage, in animals. 1. Species specificity: tumours have been induced in rats, mice and hamsters but not in guinea pigs or dogs; 2. dose-response: a threshold dose may be defined and the yield of tumours increases with the dose; 3. the amount of residual iron at the injection site: the effect is a local oncogenesis; 4. the latent period relative to life span in the species: the probable latent period in man has been estimated to be 15-20 years. Since iron-dextran was introduced 22 years ago, nine malignancies in man allegedly related to iron-complex injection have been described in five reports during the period 1960-1977. A critical review of the information available on these cases suggests that in one case only is the data sufficiencyl strong to support the probability of iron-dextran induced sarcoma in man. Soft tissue tumours of the buttock are not rare: on the basis of this single case a causal relationship in man cannot yet be made.