Bone-marrow hemosiderin iron and serum iron status markers in small-cell carcinoma of the lung

Bone marrow haemosiderin iron grade and serum (S-) iron status markers (haemoglobin (Hb), S-iron, S-transferrin, transferrin saturation, S-ferritin) were measured in 31 patients with newly discovered small cell cancer of the lung (SCCL), and compared to the values in 53 healthy control subjects. Among SCCL patients, 2 had grade 0 (absent), 5 grade (1+) (trace), 8 grade 1+ (normal), and 16 grade 2+ (increased) marrow haemosiderin iron. Median S-ferritin values in the respective groups were 38 mug/l, 243 mug/l, 384 mug/l and 433 mug/l. There was no correlation between Hb, S-iron, S-transferrin or transferrin saturation and marrow iron grade. S-ferritin displayed a correlation with marrow iron grade (r(s) = 0.40, p <0.05) but there was marked overlap between the groups. Among the controls, 5 had grade 0, 11 grade (1+), and 37 grade 1+ marrow iron. Median S-ferritin values in the respective groups were 14 mug/l, 26 mug/l and 57 mug/l. Hb, S-iron, S-transferrin, transferrin saturation and S-ferritin were all significantly correlated to marrow iron grade; S-ferritin, r(s) = 0.64, p <0.0001. In conclusion, SCCL patients have inappropriately high S-ferritin values. In SCCL, serum iron status markers, including S-ferritin, are poor indicators of marrow haemosiderin iron and thus body iron stores. Therefore, estimation of marrow haemosiderin iron or histochemical/chemical liver iron content remains the only reliable way of assessing iron stores in SCCL.