Leukemia is the most common cancer in children
Leukemia names blood cancers that usually start in bone marrow and flood the body with abnormal, immature blood cells. Genetics and environment—smoking, radiation, chemicals, some prior chemo—share suspicion. In 2015 about 2.3 million people lived with it and 353,500 died; it is the leading childhood cancer.
Acute forms explode with immature cells that crowd out healthy marrow, starving the body of haemoglobin and platelets; chronic forms accumulate more mature yet faulty white cells over months or years. Lymphoblastic lines hit lymphocyte precursors, while myeloid lines derail the marrow cells that make red cells, platelets and other white cells. Crossing speed with lineage gives four main boxes, each with subtypes. The name means white blood, after the swollen white-cell counts seen in most untreated patients.
The four behave very differently. Acute lymphoblastic leukemia accounts for three in four childhood cases but also strikes people over 65. Chronic lymphocytic leukemia mostly affects adults past 55, two-thirds of them men, with about 85 percent five-year survival. Acute myeloid leukemia is mainly an adult disease with only around 20 percent surviving five years, whereas chronic myeloid leukemia, treated with imatinib, reaches about 90 percent. Hairy cell leukemia, about 80 percent adult men, is incurable yet so treatable that ten-year survival runs from 96 to 100 percent.
Despite the childhood headline, more than nine in ten diagnoses are in adults, and the disease is commoner in rich countries. Symptoms follow from failing marrow: bruising and bleeding without platelets, infections without working white cells, breathlessness and pallor from anaemia, and in children often fever and an enlarged liver or spleen. Beyond smoking, radiation and benzene, 2009 and 2010 studies tied formaldehyde exposure to myeloid forms.
Treatment mixes chemotherapy, radiation, targeted drugs and marrow transplants, and some slow types are simply watched. American five-year survival was 69 percent for 2016 to 2022; children under 15 in wealthy countries fare better than 60 or even 90 percent depending on type, infants closer to 40 percent.
Source: Leukemia
