Treatment and course
On the day of admission, IA4 remission induction therapy (vincristine 1.5 mg/m2 intravenous injection: days 1, 8, 15, 22, and 28; daunorubicin 30 mg/m2 intravenous infusion: days 1, 8, 15, and 22; L-asparaginase 5000 U/m2intravenous infusion: days 5, 8, 11, 14, 17, 20, 23, and 26; methotrexate 12 mg bone marrow injection: days 5 and 26; cytarabine 30 mg bone marrow injection: days 5 and 26) was started according to the ALL-B12 protocol. However, the patient was not cleaning his oral cavity due to fear of tooth movement and general malaise, and his oral hygiene thus worsened. Therefore, the department continued to provide oral care during chemotherapy. Induction therapy IA4 was designed to decrease leukemia cells, alleviate symptoms, and help achieve remission. The bone marrow biopsy performed on the 14th day after the start of IA4 showed that the lymphoblasts had disappeared and the patient’s gingiva had improved with the disappearance of swelling and redness. The patient underwent remission induction therapy IA4 and was in remission on day 43 of the induction therapy. On day 54, after induction therapy IA4, he was started on early intensification therapy IB (cyclophosphamide 1000 mg/m2 intravenous infusion: days 1 and 29; cytarabine 75 mg/m2 intravenous injection: days 3–6, 10–13, 17–20, and 24–27; methotrexate 12 mg bone marrow injection: days 10 and 24; cytarabine 30 mg bone marrow injection: days 10 and 24; mercaptopurine 60 mg/m2 oral administration: days 1-28) to prevent relapse after remission and to further decrease the number of leukemia cells. During this period, mucositis was observed in the oral cavity, probably due to chemotherapy, but no tooth movement was observed. Fifty-three days after the start of early intensive therapy IB, a bone marrow examination showed that the patient was still in remission, and intensive therapy was started to eradicate leukemia cells and prevent relapse. An oral examination and imaging were performed 9 days after the start of intensified therapy and 116 days after the start of treatment for leukemia.