A report on second neo-plasms in seven children with solid tumors.

Objective: This study aims to investigate the characteristics and related high risk factors of second neoplasms after chemotherapy and radiotherapy in children with solid tumors.

Methods: The detailed clinical data of seven children with malignant solid tumors, who were treated in our department, were retrospectively analyzed, in order to summarize the clinical characteristics of the secondary onset of second neoplasms, and determined the risk factors related to the occurrence of second neoplasms.

Results: (1) Clinical characteristics: Among the seven children with malignant solid tumors, three children had rhabdomyosarcoma (3/132, 2.27%), two children had hepatoblastoma (2/313, 0.64%), one child had neuroblastoma (1/305, 0.33%), and one child had inflammatory myofibroblastoma (1/3, 33.33%). Furthermore, among these children, four children were boys and three children were girls, and their onset age ranged within 5-34 months, with a median onset age of 27 months. Moreover, among these children, three children were ≤1 year old. All second neoplasms exhibited symptoms, and the diagnosis was made after the complete remission of the first primary tumor. The time interval between these two tumors was within 17-78 months, and the median time was 38 months. Three of seven children with rhabdomyosarcoma were treated with chemotherapy in combination with radiotherapy, while four children only received the chemotherapy. The chemotherapy cycles were 6-39 times, and the median chemotherapy cycles were 10 times. Among these children, one child with relapsed stage IV rhabdomyosarcoma and one child with stage IV retroperitoneal neuroblastoma had 39 cycles and 33 cycles of chemotherapy respectively. (2) Characteristics of the accumulated doses of high-risk chemotherapy drugs: The accumulated dose of cyclophosphamide in six patients was within 2.47-44.45 g/m2, with a median of 6.14 g/m2. The accumulated dose of ifosfamide in five patients was within 13.63-96.41 mg/m2, with a median of 31.23g/m2. The accumulated dose of etoposide in six patients was within 1,237.35-3,754.95 mg/m2, with a median of 1,548.67 mg/m2. The accumulated dose of anthracyclines in seven patients was within 150.68-843.78 mg/m2, with a median of 329.73 mg/m2. The accumulated dose of vincristine in seven patients was within 3.11-18.89 mg/m2, with a median of 15.92 mg/m2. The accumulated dose of cisplatin in seven patients was within 271.23-1,681.59 mg/m2, with a median of 733.07 mg/m2. Children with abdominal inflammatory myofibroblastic tumors did not apply cyclophosphamide, ifosfamide and etoposide regimens. The main chemotherapy drugs consisted of methotrexate, pirarubicin, cisplatin and vincristine. (3) Radiotherapy doses. (4) Characteristics of second neoplasms: Among the seven children with second neoplasms, five children had leukemia, 3 patients with rhabdomyosarcoma were combined with radiotherapy. The doses of radiation were 40 and 45GY" after "(3) Radiotherapy doses (four children had acute myeloid leukemia and one children had acute B-lymphoblastic leukemia), one child had myelodysplastic syndrome, and one child had myeloid sarcoma. Furthermore, among these seven children, four children (4/7) had abnormal chromosomes, two children were normal, and one child gave up the treatment and underwent the chromosome test after the diagnosis of second neoplasms.

Conclusion: The incidence of secondary onset of second neoplasms in children with malignant solid tumors is not high, considering that this is correlated to the use of alkylating agents, topoisomerase II inhibitors, platinum-based chemotherapy drugs and radiotherapy, and associated with the chromosomal abnormalities of children.

Key Words: Chemotherapy, Children, Radiotherapy, Second malignant neoplasm, Solid tumor.