Solid malignant tumours of infancy: A retrospectiveanalysis

Background and Aim: Infantile cancers are very rare and quite different from the ones in older children in terms of anatomical site, histological features and behavior. The unique physiological and developmental characteristics of this age group require adapted multimodality approaches for diagnosis and treatment. We aimed to evaluate the incidence of different cancer subtypes and outcomes in children younger than one-year diagnosed in last 20 years. Methods: The files of 515 patients aged 0-1 years who were diagnosed with malignant tumors, treated and followed up in the Hacettepe University, Faculty of Medicine, Department of Pediatric Oncology between 01.01.2000 and 31.12.2019 were examined retrospectively. Demographic, clinical and pathological characteristics, treatments applied and treatment results were evaluated. Results: There were 515 infants, with a mean age of 6.1 ± 3.4 months, diagnosed with malignant tumors. Thirty two (6.2%) of them were diagnosed in newborn period. There were 275 male (53.4%) and 240 female (46.6%) (M/F = 1.15/1). Prenatal diagnosis was made in 4.9% of patients. The most common presentation was swelling or symptoms occuring due to mass effect (81.6%). The mean time to diagnosis was 31.3 ± 44.7 days, longest in Langerhans Cell Histocytosis (91.3 ± 59.8 days). Most common histopathological diagnoses were retinoblastomas (33.6%), neuroblastomas (27.2 %), renal tumors (10.3%) and central nervous system (CNS) tumors (9.7%), resptectively. Three most common tumors in newborn were neuroblastoma (46.9%), CNS tumors (15.6%) and renal tumors (12.5%). Bilateral tumors were found in 22.1% of cases. The 5-year and 10-year overall survival (OS) was 86.6% and 82.7%, respectively. The best 5-year OS (> 91.5%) were observed for renal tumors, retinoblastomas and neuroblastomas. Conversely, the lowest 5-year OS were observed for CNS tumors (52.5%). When non - CNS tumors are evaluated seperately, early stage tumors had better outcome compared to advanced stage tumors (5-y OS: 94.8% VS 84.8%). Conclusion: This is the first report from Turkey that assess cancer burden in children younger than one year. Our results contribute to better understanding characteristics and outcomes of the tumors in this age group.