Survival analysis of haematologic neoplasms in children and adolescents: a population-based study in a state of the Brazilian Legal Amazon.

Aims: To estimate the survival patterns of childhood leukaemias and lymphomas in Mato Grosso between 2001 and 2017.

Methods: Retrospective population-based cohort study, with case information extracted from the population-based cancer registries (PBCRs) of Mato Grosso for the period 2001-2017. Cases aged 0-19 years diagnosed with microscopically confirmed leukaemias or lymphomas were eligible. Five-year relative survival was calculated using the Eldererer II method, considering the interval between diagnosis and death, loss to follow-up or censoring, after passive follow-up in the mortality information system. Cases registered only by death certificate were excluded.

Results: 510 cases of leukaemia were analysed, with a predominance of males (56.1%) and an age range of 0-4 years (34.9%). The 5-year relative survival rate was 77.3% (95% CI: 73.6;80.9). As for lymphomas, there were 261 cases, predominantly in males and in the age group 5-9 years. The 5-year relative survival rate was 84.7% (95% CI: 78.3;88.9), with a better prognosis for females and 87.7% (95% CI: 80.8;95.1) in the 5-9 years age group.

Conclusion: The relative survival rates of childhood leukaemia and lymphoma in the state of Mato Grosso were lower than those of developed countries. The importance of early diagnosis and timely treatment for better outcomes is highlighted. The importance of using and continuously improving the quality of information from PBCRs in the state of Mato Grosso is highlighted.