Background: Hepatoblastoma in children of very low birthweight (< 1500 g) is increasing in Japan and this has suggested the presence of either a genetic or environmental etiology. This study was aimed at revealing common prenatal and postnatal histories, including family history of hepatoblastomas in children of very low birthweight.
Methods and results: The medical records of 15 patients, nine boys and six girls, were reviewed. The patients were diagnosed at the age of 6-77 months (median 16 months). Their birthweight ranged from 560 to 1380 g (median 826 g) and the gestational age was 23-33 weeks (median 25 weeks). No parents were exposed to any occupational risk factors and there were no characteristic features in the parents' history or the maternal reproductive history, although one patient was born to a mother who had taken a contraceptive before she got pregnant with the patient as a result of in vitro fertilization. A ventricular septal defect and an atresia of the external auditory canal were congenital anomalies seen in the patients, but congenital anomalies associated with hepatoblastoma were not seen. Early postnatal illnesses included respiratory distress syndrome in six patients, symptomatic patent ductus arteriosus in three patients, chronic lung disease in seven patients, cytomegalovirus hepatitis in one patient and cholelithiasis in one patient. Oxygen therapy was given to 13 patients for a period of 4-508 days (median 112 days) and lengths of oxygen therapy and assisted ventilation were significantly longer in patients with a stage IIIB or IV tumor than those with a stage II or IIIA tumor (P = 0.0040 and 0.0190, respectively). Furosemide was used in 13 patients for a period of 6-460 days (median 88 days) and the length of the treatment was also significantly longer in patients with advanced tumors (P = 0.0420). Among the patients at 23-25 weeks of gestation, these treatments tended to be longer in patients with a stage IIIB or IV tumor than those with a stage II or IIIA tumor.
Conclusions: These results suggest the presence of an environmental etiology, rather than a genetic one, which is responsible for the development of hepatoblastoma in children of very low birthweight. Close monitoring of the children after being discharged from the neonatal intensive care unit is essential and a case-control study is necessary to identify risk factors for hepatoblastoma in children of very low birthweight.