Long-Term Follow-Up of Children Treated for Acute Leukemia Focusing on Development of Malignant and Non-Malignant Neoplasms

Although the introduction of modern treatment strategies has resulted in an excellent prognosis for leukemia, it is also associated with various late effects. Survival data from all children with leukemia diagnosed after 1946 were used to calculate survival rates. Analyses of late effects were performed on patients diagnosed after 1968. The survival rate before 1964 was 0.0 at 302 months (n=240) for acute leukemia and 0.937 ± 0.031 at 212 months (n=64) for Acute Lymphocytic Leukemia (ALL) after 1996. Second Primary Neoplasms (SPNs) developed in 11 survivors with ALL, but in none with AML: 2 breast carcinomas, 1 colon carcinoma, 1 urinary bladder carcinoma, 2 thyroid carcinomas, 1 thyroid adenoma, and 4 meningiomas. The overall incidence of SPNs 29 years after the diagnosis of primary cancers was 10.0%. Furthermore, intracranial cavernous hemangiomas were detected in 3 patients 13 to 31 years after cranial irradiation. In addition to the well-known finding that patients treated with Prophylactic Cranial Irradiation (PCI) are at risk of developing brain tumors, this study revealed that thyroid carcinoma may develop even after PCI if patients are very young. Furthermore, cavernous hemangioma may be one of the serious complications of cranial irradiation because it may result in intracranial hemorrhage. Its symptomatic form appears to be rare but can be potentially serious condition because it is frequently detected by MRI screening. Although the prognosis of leukemia in Japan has markedly improved, this improvement has been associated with serious health issues. Lifelong follow-ups are needed for the survivors of childhood leukemia.