Childhood Leukemia and Primary Prevention

Abstract

Leukemia is the most common pediatric cancer, affecting 3,800 children per year in the United States. Its annual incidence has increased over the last decades, especially among Latinos. Although most children diagnosed with leukemia are now cured, many suffer long-term complications, and primary prevention efforts are urgently needed. The early onset of leukemia – usually before age five – and the presence at birth of “pre-leukemic” genetic signatures indicate that pre- and postnatal events are critical to the development of the disease. In contrast to most pediatric cancers, there is a growing body of literature – in the United States and internationally – that has implicated several environmental, infectious, and dietary risk factors in the etiology of childhood leukemia, mainly for acute lymphoblastic leukemia, the most common subtype. For example, exposures to pesticides, tobacco smoke, solvents, and traffic emissions have consistently demonstrated positive associations with the risk of developing childhood leukemia. In contrast, intake of vitamins and folate supplementation during the pre-conception period or pregnancy, breastfeeding, and exposure to routine childhood infections have been shown to reduce the risk of childhood leukemia. Some children may be especially vulnerable to these risk factors, as demonstrated by a disproportionate burden of childhood leukemia in the Latino population of California. The evidence supporting the associations between childhood leukemia and its risk factors – including pooled analyses from around the world and systematic reviews – is strong; however, the dissemination of this knowledge to clinicians has been limited. To protect children’s health, it is prudent to initiate programs designed to alter exposure to well-established leukemia risk factors rather than to suspend judgement until no uncertainty remains. Primary prevention programs for childhood leukemia would also result in the significant co-benefits of reductions in other adverse health outcomes that are common in children, such as detriments to neurocognitive development.

Correlates of Prenatal and Early-Life Tobacco Smoke Exposure and Frequency of Common Gene Deletions in Childhood Acute Lymphoblastic Leukemia

“…A small proportion of cases can be explained by well-established factors such as congenital cancer predisposition syndromes or exposure to ionizing radiation. In addition, several environmental exposures have been associated with increased ALL risk, including tobacco smoke, pesticides, paint, and air pollution (2, 3). Despite high cure-rates for ALL, survivors face long-term treatment-related morbidities and mortality (4), therefore prevention remains an important goal.…”

Maternal residential pesticide use and risk of childhood leukemia in Costa Rica

“…Evidence suggests that childhood leukemia is a multi‐step process, with initiation taking place in utero and progression of acute disease taking place after birth,2 and our results highlight the need for more research investigating the mechanisms of in utero leukemia initiation in boys and girls. Further research may benefit from investigating gene‐environment interactions and mechanisms of pesticide toxicity to elucidate sex differences in the etiology of childhood leukemia and also in incidence and survival rates 46…”

Carcinógenos ambientales asociados a cáncer infantil

“…han identificado factores protectores relacionados con el patrón dietético y la reducción del riesgo de cáncer, tales como la lactancia materna por ingesta de nutrientes esenciales para el recién nacido y cebados inmunológicos, que reducen el riesgo de desarrollar leucemias en los niños (25) ; una dieta abundante en verduras y frutas aporta vitaminas y minerales anti-cancerosos, antiproliferativos, y anti-inflamatorios, que reducen el riesgo de cáncer de esófago, estómago y cáncer colorrectal (23,24,26) ; el consumo regular de naranjas y bananos durante los dos primeros años de vida reduce el riesgo de desarrollar leucemia infantil (26) .…”