2022 Volume 47 Issue 1 Pages 1-18
Background: Oral mucositis is the most common adverse event seen in chemotherapy patients. While it is widely accepted that salivary leucocytes contribute to maintain oral mucosal health, their association with oral mucositis occurred in patients during chemotherapy is unknown.
Aim: As a preliminary study, we examined the reliability and applicability of salivary leukocyte assays with a commercially available testing device （SillHa, Arkrey, Japan） in healthy volunteers. In subsequent clinical observational study using the testing device, we aimed primarily to elucidate the association of the occurrence of oral mucositis with changes in leukocyte levels of saliva and peripheral blood in chemotherapy patients.
Methods: SillHa （Arkrey, Japan） was used as a commercially available testing device. Leukocyte levels in saliva samples from 50 healthy adult volunteers were determined both with SillHa and CD45 positive cell counts by flow cytometry. For subsequent clinical longitudinal study with the occurrence of oral mucositis as the primary outcome, thirty-one patients undergoing chemotherapy at Iwate Medical University Hospital participated in the study after providing informed consent for use of the findings in an anonymous manner. Data regarding attributes, lifestyle factors, and treatments received for the primary disease were obtained from medical records. Each underwent an oral examination before starting chemotherapy （baseline）. Thereafter, leukocyte levels in saliva and peripheral blood were determined approximately every two days. This study followed the Declaration of Helsinki and STROBE statement for reports of observational studies.
Results: The correlation coefficient between measurements by SillHa and flow cytometry showed high value （r=0.818, p<0.001）. In the patients undergoing chemotherapy, oral mucositis occurred in 41.9% participants during the observation periods. Among the data analyzed in this study, the strongest relationship with occurrence of oral mucositis was found to be number of days from lowest recorded salivary leucocyte count to recovery to more than 50% of the baseline value. In ROC analysis, the area under the curve was 0.771, indicating a high capacity to discriminate between patients with and without occurrence of oral mucositis.
Conclusion: The present findings indicate that changes in salivary leukocyte levels measured with a commercially testing device is useful to predict occurrence of oral mucositis in patients receiving chemotherapy.
