Association of plasma methotrexate, neutropenia, hepatic dysfunction, nausea/vomiting and oral mucositis in children with cancer.

Oral mucositis is a major toxicity associated with high-dose methotrexate (HD-MTX) therapy in the treatment of children with acute lymphoblastic leukaemia and osteosarcoma. This pilot matched case-control study investigated the associations between plasma concentration of MTX at 42 (p-MTX(42h)) and 66 (p-MTX(66h)) h, absolute neutrophil count (ANC) < or = or >1.0 x 10(9)/l, serum transaminases (ASAT/ALAT) < or > or =58 U/l, WHO < or > or =grade 2 nausea/vomiting and WHO < or > or =grade 2 oral mucositis. In this study, 11 children with WHO > or =grade 2 oral mucositis were compared with 17 control children matched for age, diagnosis and MTX-dosage. The results indicated that children with p-MTX(42h) > or = 1.0 micromol/l had an odds ratio (OR) of 4.3 of developing oral mucositis when compared with the referent group of children who had p-MTX(42h) < 1.0 micromol/l. Children with p-MTX(66h) >= 0.2 micromol/l had an OR of 8.2 of developing oral mucositis when compared with the referent group of children who had p-MTX(66h) < 0.2 micromol/l. Children with ANC < or = 1.0 x 10(9)/l had an OR of 1.2 of developing oral mucositis when compared with the referent group of children who had ANC > 1.0 x 10(9)/l. In comparison with the referent group of children, who had <58 U/l ASAT/ALAT, those with ASAT/ALAT > or = 58 U/l had an OR of 1.2 of developing oral mucositis. Finally, children with WHO grade > or =2 nausea/vomiting had an elevated risk of developing oral mucositis when compared with the referent group of children who had WHO grade <2 nausea/vomiting (OR = 8.7). In conclusion, the results in this preliminary study provide support for the hypothesis that the risk of oral mucositis is associated with the plasma MTX concentration at 66 h and the level of nausea/vomiting.