This review evaluated the best available evidence concerning the effectiveness of photobiomodulation compared to oral cryotherapy in oral-mucositis prevention among patients with hematological stem cell transplantation (HSCT) receiving chemo-conditioning.
An extensive search for published and unpublished studies was conducted in 11 electronic databases and reference lists. Only randomized controlled trials (RCTs) were included. Two reviewers independently screened relevant studies for eligibility, extracted data using a standardized data collection form, and appraised data using the Cochrane Risk of Bias Tool and Grading Recommendations, Assessment, Development and Evaluation (GRADE). Meta-analyses using a random-effect model was performed using Review Manager software. Subgroup analyses were conducted to examine the differential effect of interventions across subgroups and to explore potential sources of heterogeneity. Meta-analyses included 18 RCTs (involving 1,018 patients). Both photobiomodulation and cryotherapy were effective in reducing oral-mucositis severity, severe oral-mucositis incidence, duration, and pain with small to large effect sizes. No significant differences were detected between photobiomodulation and cryotherapy across all outcomes. Subgroup analyses showed significant differences for chemo-conditioning regimens. The overall Grading Recommendations, Assessment, Development and Evaluation quality of evidence was low.
Both photobiomodulation and cryotherapy were effective nonpharmacological oral-mucositis prophylaxis and analgesia, with no significant difference in effectiveness. Chemo-conditioning regimens may influence their effectiveness. Future RCTs may directly compare the effectiveness of photobiomodulation and cryotherapy on the HSCT patients. Rigorous cost-effectiveness studies are also required.
Photobiomodulation and cryotherapy can be offered to HSCT patients in clinical settings. A clinical guideline of both interventions can be also developed.

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