There are number of hereditary cancer syndromes which may result in neoplasms in children and/or adolescents, for example: Li-Fraumeni syndrome, PTEN hamartoma tumor syndrome, Fanconi anemia, etc. Number of cancer screening/surveillance protocols have been established in order to decrease morbidity and mortality for individuals with pathogenic germline alterations known to cause hereditary cancer syndromes. For example, pathogenic germline TP53 mutation carriers may undergo surveillance which can include number of tests including annual whole body MRI, annual brain MRI, comprehensive blood tests. Such comprehensive surveillance protocols and early tumor detection are associated with improved long-term survival . Including in such protocols ctDNA analysis of blood and urine may help to better understand genetics of cancer progression and also potentially improve early tumor detection. Especially if such analysis could be combined with analysis of tissues from biopsies and resections of neoplasms detected during surveillance.
 Villani A, Shore A, Wasserman JD, Stephens D, Kim RH, Druker H, et al. Biochemical and imaging surveillance in germline TP53 mutation carriers with Li-Fraumeni syndrome: 11 year follow-up of a prospective observational study. Lancet Oncol 2016;17:1295–305