Low casuistry that did not allow the study to continue

Among the different types of cancer that most affect children, leukemia is the principal. One of the main treatments for leukemia is chemotherapy. Among the most common side effects of chemotherapy are nausea and/or vomiting, diarrhea, fatigue, alopecia, neuropathy, opportunistic infections, and oral mucositis. It is still necessary to establish which microorganisms are predominant in the oral microbiota of children with leukemia, which factors influence it, what is its relationship with oral mucositis and what is their impact in the quality of life. To better understand the risks of secondary infection, it is important to develop preventive and/or therapeutic strategies to control the side effects of antineoplastic treatment in the mouth that may negatively impact the quality of life, to expose the risk of death as well as raise hospital costs for the care of children with leukemia. Objective: To identify the clinical characteristics of the oral condition, types of microorganisms of the oral microbiota, and quality of life in children/adolescents with acute lymphoid leukemia and acute myeloid leukemia before and during antineoplastic treatment, and compare them with healthy children/adolescent individuals. Methodology: Longitudinal, case-control study, with a convenience sample. The study group, composed of children/adolescent individuals who have a definitive diagnosis of acute lymphoid leukemia or acute myeloid leukemia. The control group, non-syndromic children/adolescents, with no history of cancer, matched by age and gender. The clinical condition of the mouth will be evaluated by means of indexes: dental caries index (dmft index), gingival index (GA), and simplified oral hygiene index. The assessment of the quality of life through the ohip-14 and POS-version14 quality of life questionnaire and microbiological evaluation of saliva through MALDI-TOF analysis. Statistical analysis will be performed through relative risk for cohort study with more than three paired groups. Odds ratio, for the control group more than three controlled groups and Mcnemere, for comparison with the control group, for more than three paired groups.

In children, non-communicable diseases such as cancer are increasing every year. It became a priority on the global child health agenda. Each year, there were an estimated 30.000 new cases of cancer in children/adolescent individuals. In Brazil, between 2018-2019, there were 12.500 new cases of cancer in children and adolescents up to 19 years of age. The mortality rate was 7.917 cases.

Among the types of cancer that most affect children, leukemia is the most prevalent. In 2018, there was a forecast of 437.033 new cases of leukemia with a mortality of 309.006 individuals around the world.

One of the main treatments for leukemia is chemotherapy, the side effects can affect different parts of the body that may present since the beginning of the treatment. Chemotherapy produces systemic toxicity resulting in anemia, leukopenia, and thrombocytopenia that is more intense in the treatment of oncohematological diseases when compared to solid tumors. Among the most common side effects of chemotherapy are included nausea and/or vomiting, diarrhea, fatigue, alopecia, neuropathy, opportunistic infections, and oral mucositis.

Some studies reported that the intensity of oral mucositis, as well as the risk of sepsis from secondary infection in the mouth of individuals with cancer, they can be influenced by some specific microorganisms present in the oral cavity. Factors such as oral hygiene, presence of dental caries, and periodontal disease may be related to the type of microorganisms present in the oral cavity. There is a lack of studies about microbiota oral in leukemic children. Oral microbiota in children with leukemia is predominantly composed of gram-positive microorganisms such as Streptococus viridans, Streptococous mutans and Lactobacillus when compared to adults oral microbiota where gram-negatives microorganisms such as Klebsiella spp., E coli, Enterobacter, Pseudomonas spp. predominate. It is noteworthy that it is necessary to establish what kind of microorganisms are predominant in the oral microbiota of children with leukemia, also which factors influence it, and what is the relationship among the oral mucositis, general clinical status, and quality of life of the children/adolescent with cancer.

Therefore, it is important to identify the risks of secondary infection in oral cavity, to be able to develop preventive and/or therapeutic strategies to control the side effects of antineoplastic treatment in the mouth that can negatively impact the quality of life, expose the risk of death as well as raise hospital costs for the care of children with leukemia.

Inclusion Criteria:

• Patients who, based on the agreement of parents and/or guardians, agree to participate in the research with a signed "Informed Consent Form"
• Patients from 3 to 17 years of age
• Patients older than 6 years must not only have parental and/or guardian authorization must have the consent term
• Patients who have not started antineoplastic treatment
• Patients with ALL only with BFM protocol
• AML patients with BFM protocol only

Exclusion Criteria:

• Responsible for patients who do not sign the free and informed consent form.
• Patients under three years of age and over 17 years of age
• Children older than six years who do not agree to the term of assent
• Patients who have started antineoplastic treatment
• Patients with syndromes and/or other systemic diseases associated with the diagnosis of lymphoid and acute myeloid leukemia
• Neoplasms other than lymphoid leukemia or acute myeloid

The study group will be composed of children/adolescent individuals who have a definitive diagnosis of lymphoid leukemia or acute myeloid leukemia, who will be invited to participate in the research, regardless of race or gender.