Epidemidogical Analysis of 982 Hospitalized Cases of Childhood Acute Lymphoblastic Leukemia

OBJECTIVE: To understand the epidemiological characteristics of childhood acute lymphoblastic leukemia (ALL) by analyzing the clinical data of 982 patients. METHODS: A retrospective analysis was performed on 982 children with ALL who were admitted to our center from April 2008 to May 2015. The sex, age and season of onset, risk factors related with the disease, and molecular biological characteristics were analyzed. RESULTS: The ratio of male to female in ALL was 1.5ratio1, the median age of onset was 5 years old, and the peak age of onset was 2 to 5 years old. The peak season of onset was spring. Analysis of birth and feeding history showed that the children born after normal period of gestation accounted for 98.0%. Among the born children 55.9% of children were born with natural lobour, and 44.1% of children were born by cesarean section. The breast feeding children accounted for 79.8%, while artificial/mixed feeding children accounted for 20.2%. The median birth weight was 3.5 kg (1.8-7.2 kg). There were 34 cases (3.5%) with abnormal birth history, including 10 cases with umbilical cord around the neck. 31.4% of the patients had a recent history of house decoration, and the median exposure time to decoration environment was 12 months (1-36 months). Among the first to third grade relatives of the children, 44 patients (4.5%) sufferd from blood system diseases, including 23 patients with leukemia, 53 (5.4%) had malignant tumors, and most of them were lung cancer, digestive system tumors and breast cancer. The immunophenotype showed that B-ALL accounted for 90.7% and T-ALL accounted for 9.3%. In molecular biological tests, TEL/AML1 positive patients accounted for 21.0%, E2A/PBX1 positive patients accounted for 5.2%, BCR-ABL positive patients accounted for 6.1%, and MLL positive patients accounted for 2.5%. CONCLUSION: The childhood ALL occurs in more boys, the peak age of onset is 2-5 years old, the peak season of onset is spring, the peak of birth season is autumn and winter, the proportion of cesarean section, high birth weight and non-breastfeeding after birth are higher than the average value of infants in most parts of the country during the same period. The proportion of childhood ALL patient's exposure to ionizing radiation and house decoration environment, and relatives with history of blood and malignant tumors are high.