RESUMO
AIM: The contribution of host genetic factors in oropharyngeal mucositis is not fully understood. Therefore, we conducted this study to determine possible associations of age, sex, underlying disease, type of chemotherapy and ABO blood group antigens with the risk of chemotherapy-induced oropharyngeal mucositis. METHODS: A total of 641 patients (395 boys and 246 girls; mean age 6.82+/-4.08 years) treated by standard chemotherapy for different type of malignancies were enrolled in the study. Mucositis was scored using the WHO scale. RESULTS: Oropharyngeal mucositis was found in 65.4% of our population. Patients with hematological malignancies (RR=1.87; 95% CI 1.33-2.67; P<0.0001) and under antimetabolities drugs (RR=1.88; 95% CI 1.33-2.63; P<0.0001) were associated with increased risk of oropharyngeal mucositis. Also, patients with blood group O were at higher risk (RR=2.86; 95% CI 2.03-4.02; P<0.0001) compared to patients with blood type A (RR= 0.47; 95% CI 0.33-0.66; P<0.0001) and blood type B (RR=0.59; 95% CI 0.38-0.91; P= 0.01). No relationship was found between oropharyngeal mucositis and age or sex. CONCLUSIONS: To our knowledge this is the first report demonstrating an association between ABO blood group and oropharyngeal mucositis. Further investigations are needed for a better understanding of this relationship.