Iron deficiency in cancer patients

ABSTRACT Anemia is a frequent complication in cancer patients, both at diagnosis and during treatment, with a multifactorial etiology in most cases. Iron deficiency is among the most common causes of anemia in this setting and can develop in nearly half of patients with solid tumors and hematologic malignancies. Surprisingly, this fact is usually neglected by the attending physician in a way that proper and prompt investigation of the iron status is either not performed or postponed. In cancer patients, functional iron deficiency is the predominant mechanism, in which iron availability is reduced due to disease or the therapy-related inflammatory process. Hence, serum ferritin is not reliable in detecting iron deficiency in this setting, whereas transferrin saturation seems more appropriate for this purpose. Besides, lack of bioavailable iron can be further worsened by the use of erythropoiesis stimulating agents that increase iron utilization in the bone marrow. Iron deficiency can cause anemia or worsen pre-existing anemia, leading to a decline in performance status and adherence to treatment, with possible implications in clinical outcome. Due to its frequency and importance, treatment of this condition is already recommended in many specialty guidelines and should be performed preferably with intravenous iron. The evidences regarding the efficacy of this treatment are solid, with response gain when combined with erythropoiesis stimulating agents and significant increments in hemoglobin as monotherapy. Among intravenous iron formulations, slow release preparations present more favorable pharmacological characteristics and efficacy in cancer patients.

Transferrin saturation as a possible marker of hematological recovery after hematopoietic stem cell transplantation: [letter to the editor]

Alterações no perfil de ferro já foram descritas em pacientes submetidos à quimioterapia de altas doses com transplante de células precursoras hematopoiéticas (TCPH), e uma possível relação entre o metabolismo do ferro e a reconstituição hematopoiética pós-transplante, embora proposta, ainda carece de confirmação. Com o objetivo de avaliar as alterações do perfil de ferro e a sua correlação com a recuperação hematológica pós-TCPH, foram determinados a saturação da transferrina (ST), ferro e ferritina séricos em 21 pacientes submetidos a TCPH, antes do transplante e prospectivamente no dia 0, no dia +14 e no dia +180. Após a quimioterapia de altas doses, todos os parâmetros analisados se elevaram acentuadamente no dia 0 e permaneceram ainda alterados no dia +14; após 180 dias, observou-se uma tendência de retorno para valores próximos aos obtidos antes do transplante. No dia +14, os valores de ST apresentaram forte correlação inversa com a contagem absoluta de leucócitos (p<0,0001) e de reticulócitos (p<0,05), e uma correlação direta com o tempo de enxertia (p<0,0001). Nossos resultados demonstram que o perfil de ferro se altera de forma aguda e significativa após a quimioterapia de altas doses com TCPH e que tais alterações estão aparentemente correlacionadas com a atividade hematopoiética após o transplante.

Avaliação laboratorial da toxicidade molecular em eritrócitos talassêmicos / Laboratorial evaluation of molecular toxicity in thalassemic erythrocytes

Oxygen-derived free radical damage is associated with the molecular toxicity of hemoglobin. Especially in thalassemia syndromes, this toxicity has a relationship with "free" alpha globin concentrations. This study of beta thalassemia trait blood samples from 39 individuals shows that the evaluation of methemoglobin is a sensitive method of indicating molecular toxicity and the superoxide dismutase concentration revealing the intensity of oxidative stress of this process.