Changes of cariogenic microflora in children receiving chemotherapy

The prognosis of children with cancer has improved with 5-year survival rates for acute leukemia over 70%. Studies about oral microbiologic changes during chemotherapy are few and mainly on adult population. Objectives: The aim of the study is to investigate the changes in cariogenic microflora of children with acute leukaemia treated with chemotherapy. Methods: 18 acute leukemia children being treated with chemotherapy at National Taiwan University Hospital, were examined between 8 months and 1 year to determine the changes in their oral conditions, before oncology treatment and then at planned intervals. Oral conditions were recorded. Unstimulated saliva were collected to assess levels of bacteria. Results: There was significant difference ( p < 0.01 ) for counts of S. mutans at different treatment stages. Sensitivity tests showed that S. mutans was sensitive to the cytotoxic drugs, idarubicin and methotrexate. These two drugs were probably responsible for the fall in S. mutans counts. Resistant strain development was suspected and further studies were needed. Significant differences were also found in the counts of S. mutans and lactobacillus between the study and reference groups before chemotherapy. Untreated caries lesions may contributed to the results. Conclusions: Decreases in counts of caries-related bacteria are found during the period of cytotoxic drug therapy. Changes of oral conditions during chemotherapy are on soft tissue mainly. Though decreases in the counts of caries-related bacteria were found, it is imperative to keep oral hygiene care and regular dental check-up for children receiving chemotherapy.