Diagnosis, treatment and prognosis of secondary leukemia in children with malignant solid tumor

Objective To explore the clinical characteristics, types, treatment and prognosis of secondary leukemia due to chemotherapy and radiotherapy in children with malignant solid tumor. Methods Followed up to January 2019, we confirmed 3 children with secondary leukemia from 2 269 cases of malignant solid tumor children who were diagnosed and treated from May 2007 to May 2017 in Beijing Tongren Hospital, and they were chosen as research subjects. The clinical data of 3 children including clinical characteristics, treatment and prognosis of primary malignant solid tumors and secondary leukemia were analyzed retrospectively. This study was in line with World Medical Association Declaration of Helsinki revised in 2013. For the treatment of the children, their families had informed consents. Results ① Types of primary malignant solid tumors and diagnosis age of children: Primary malignant solid tumors of 3 children were 4 stage of neuroblastoma (NB)(patient 1), Ⅲ stage of left orbit rhabdomyosarcoma (RMS)(patient 2) and extraocular stage of left retinoblastoma (RB)(patient 3). All of male and the diagnosis age of primary diseases of children were 2 years and 1 month, 8 years and 3 years old. ② The therapy regimen of primary malignant solid tumor and curative effect: Patient 1 was treated with 29 cycles of chemotherapy, surgery and autologous peripheral blood hematopoietic stem cell transplantation (HSCT), and received very good partial remission (VGPR). Patient 2 was treated with 12 cycles of chemotherapy, surgery and radiotherapy, and received complete remission (CR). Patient 3 was treated with 14 cycles of chemotherapy and surgery, and received CR. ③ Characteristics of chemotherapy drugs for malignant solid tumors: ALL of 3 children received chemotherapy drugs with vincristine and etoposide. The longest application periods were NB child received 15 cycles of vincristine and RB child received 14 cycles of etoposide. The longest application periods of platinum drugs were RB child received 14 cycles of carboplatin and NB child received 8 cycles of cisplatin. ④ Diagnosis, treatment and prognosis of secondary leukemia: The onset time of secondary leukemia to chemotherapy stop time of primary tumor of NB, RMS and RB children were 6, 25 and 10 months, respectively. The clinical leukemia types were NB and RMS children with acute myeloid leukemia (AML, M2 type) and RB child with acute B-lymphocytic leukemia (B-ALL, L2 type) . After chemotherapy for secondary leukemia, children with NB and RMS were dead 12 and 5 months after diagnosis of AML, respectively. The RB child with B-ALL achieved CR and free event survival after chemotherapy and haploidentical allogeneic HSCT. Conclusions Long period of chemotherapy for malignant solid tumor might be a main reason of resulting in secondary leukemia. Therefore, the monitoring of leukemia related examinations should be taken after malignant solid tumor chemotherapy, to achieve early diagnosis and treatment for secondary leukemia. Key words: Neuroblastoma; Rhabdomyosarcoma; Retinoblastoma; Neoplasms, second primary; Leukemia; Drug therapy; Radiotherapy; Child