Cryotherapy for oral mucositis in cancer: review of systematic reviews and meta-analysis

Background: One of the most common side effects of cancer treatment is oral mucositis. Although studies have shown that oral cryotherapy has a favourable effect on oral mucositis, the reliability of the results is questionable. Objective: The goal of this umbrella review was to provide insight into the effects of oral cryotherapy against oral mucositis in patients with cancer, as well as to assess the certainty of this evidence. Method: Studies were searched for through PubMed, Scopus and Web of Science, with no restrictions until August 2021. The risk ratio (RR) and 95% CI for each meta-analysis were recalculated using a random-effects model, and the certainty of the evidence was judged using Grading of Recommendations Assessment, Development and Evaluation. Results: Ten meta-analyses including 25 original RCTs that fit our inclusion criteria were included. The use of oral cryotherapy markedly reduced the occurrence of overall (RR 0.72, 95% CI 0.64 to 0.83, n=20 trials), moderate to severe (RR 0.60, 95% CI 0.45 to 0.80, n=16 trials) and severe oral mucositis (RR 0.48, 95% CI 0.34 to 0.67, n=16 trials), as well as average severity score of oral mucositis (standardised mean difference=-0.94, 95% CI -1.28 to -0.59, n=4 trials) in comparison to a control group; however, the certainty of evidence for all outcomes was rated very low. Conclusion: In patients with cancer, oral cryotherapy appears to greatly lower the severity and occurrence of oral mucositis, but, with very low certainty of evidence.