This study proposes to investigate the effect of treatment of neuroblastoma on nutritional status, assessed by body mass index (BMI) z score, and body composition evaluated by mid-upper arm circumference (MUAC), from diagnosis through 1-year post end of treatment. The study also aims to investigate the nutritional status and its role in toxicities, infection, survival rates, disease relapse, cost of care and readmission rates, as well as health-related quality of life. The study will take place in Sao Paolo in Brazil, where an estimated sample of 50 children with neuroblastoma will be recruited for the period of 2 years.

In Brazil, cancer represents the leading cause of death by disease in children and adolescents from 1 to 19 years old. Neuroblastomas correspond to nearly 10% of all cancer diagnoses among children younger than 15 years of age, with an incidence of 1 case per 100,000 children of this age group. About 500 new cases of neuroblastoma (NB) are diagnosed annually in Brazil. The complexity and intensity of treatment result in several treatment-related toxicities (TRT) that make it challenging to maintain nutritional status in these nutritionally at-risk patients. In Brazil, up to 26% of undernutrition at diagnosis has been found in patients with solid tumors. In neuroblastoma, high prevalence rates of malnutrition have been reported elsewhere with up to 80% of children at diagnosis and 20-50% during treatment classified as undernourished. It's important to underscore that nutritional status is a modifiable risk factor, therefore it needs more attention and close monitoring. It is important to better comprehend the effect of treatment for neuroblastoma on nutritional status and body composition, for which prospective longitudinal studies are required. Therefore, in this prospective cohort study, the investigators will evaluate the fluctuations in nutritional status over the course of treatment in children with neuroblastoma at the study center in São Paulo, Brazil. The results of this study will drive the development of evidence-based guidelines for the nutritional care of children with neuroblastoma and set research priorities for subsequent investigations.

Inclusion Criteria:

• Diagnosis of high-risk neuroblastoma at ITACI, according to the Pediatric Oncology Group (POG)/Children's Cancer Study Group (CCG) classification (International Neuroblastoma Staging System (INSS) stage)
• Age under 18 years
• Informed consent from a legal guardian to participate in the study

Exclusion Criteria:

• Patients who have received previous chemotherapy
• First assessment performed more than 48 hours after the beginning of treatment

Demographic variables will be collected from medical records, including date of birth, sex, city/state/country of residence, date of diagnosis and ethnicity. Socioeconomic data (per capita annual income and living conditions) will be drawn from the institutions' social work service charts. The data will be collected in hospital - Instituto de Tratamento do Câncer Infantil, in Sao Paolo, Brazil.

The investigators will also collect clinical outcome data from the medical chart. The incidence of infectious toxicity, all Grade 3 and 4 toxicities (defined by the National Cancer Institute (NCI) Common Toxicity Criteria (CTC)), death, disease relapse or progression, number of days in the hospital and delays in treatment will be documented during each cycle.

The database is secured in Brazil research site at ITACI. De-identified data is shared with Columbia University Medical Center via REDCap database system - managed by Columbia University