Global patterns of leukemia by subtype, age, and sex in 185 countries in 2022

In 2022, leukemia ranked as the second most common hematological malignancy after non-Hodgkin lymphoma worldwide. However, updated global estimates of leukemia incidence by subtype are unavailable. We estimated leukemia incidences for different leukemia subtypes by country, world region, and human developmental index using data from the Cancer Incidence in Five Continents databases combined with the GLOBOCAN 2022 estimates of leukemia in 185 countries. We estimated sex-specific age-standardized rates (ASRs) per 100 000 for children (0-19 years) and adults (20+ years). In adults, the most common leukemia worldwide was AML (males: 38%, ASR = 3·1; females: 43%, ASR = 2·4), followed by CLL (males: 28%, ASR = 2·2; females: 24%, ASR = 1·3). In very high HDI countries, the ASR of CLL was higher than the ASR of AML among males (5·2 versus 4·3, respectively) and similar among females (2·9 and 3·0, respectively). In children, the most common leukemia was ALL (boys: 70%, ASR = 2·4; girls: 68%, ASR = 1·8) followed by AML (boys: 22%, ASR = 0·76; girls: 25%, ASR = 0·65). ALL proportions varied across world sub-regions from 57 to 78% among boys, and from 49 to 80% among girls. Our findings suggest clear geographical patterns of leukemia subtypes in adults and children. Further research into underlying causes that explain these variations is needed to support cancer control strategies for prevention and plan national healthcare needs.