ИСТИНА

Background/Objectives:Over the past decades, there has been a growth of multiple primary tumors (MPT) throughout the world, in both adults and children. The aim was to study the features of the clinical presentations of multiple primaries sporadic and hereditarily determined malignant tumors in children.Design/Methods:From 1998 to 2012 among 5875 patients were revealed 104 children who had multiple primary malignant tumors (MPMT). The analyses of clinical data such as: the frequency of occurrence of second tumors, the interval of their appearance from the primary diagnosis was carried out both in the group as a whole and in separate types of cancer.Using methods Next Generation Sequencing (NGS) and Multiplex Ligation-dependent Probe Amplification (MLPA) allowed to reveal germinal mutations in 12 children with MPMT.Results:The second primary tumor detected in 104 (1.8%) children.The age of patients at the time of occurrence of the second malignant tumor ranged from 2.8 to 28 years. The second tumors occurred significantly more frequently in the group of primary hematopoietic tumors, compared with the group of solid tumors - 8.7% versus 3.4%, respectively (p <0.0001). In children with MPMT were found tumors that occur in common the most frequency, such as retinoblastoma patients have an increased risk of developing sarcoma, patients with Hodgkin's lymphoma have an increased risk of developing leukemia. The germline mutations in TP53, RB1, CHEK2, FANCN/PALB2, MLH1, PMS2 genes identified in 12 patients. They were associated with hereditary syndromes and an increased risk of developing second tumors, among which: sarcomas, brain tumors, hematopoietic tumors were the most frequent. It was shown that the second tumors can appear at the any age. Conclusions:Children who survived the treatment of the first tumor in later life should be monitored annually. Clinical management of children with MPT requires a multidisciplinary approach. October 23-26, 2019 in Lyon, France