Summary of outcomes of low level laser therapy as compared to placebo/no treatment.

Abbreviations: RR - risk ratio; SMD - standardized mean difference; WMD – weighted mean difference; CI – confidence interval; *Maximum anticipated mucositis was week 6±1 in head and neck cancer radiotherapy/chemo-radiotherapy trials and day 10±4 in chemotherapy and hematopoietic stem cell transplantation trials (from date of chemotherapy initiation and stem cell infusion respectively). ** Severe pain defined as a visual analogue scale score >7. ¥All analyses used a random-effect model. A risk ratio <1 and a standardized mean difference or weighted mean difference <0 with 95% CIs that do not include 1 or 0 respectively, suggest that low level laser is better than placebo/no therapy. Summary of outcomes of low level laser therapy as compared to placebo/no treatment.