Bjordal, J.M., Bensadoun, R.J., Tuner, J., Frigo, L., Gjerde, K., & Lopes-Martins, R.A. (2011). A systematic review with meta-analysis of the effect of low-level laser therapy (LLLT) in cancer therapy-induced oral mucositis. Supportive Care in Cancer, 19, 1069–1077.

Review the effects of low level laser therapy (LLLT) in prevention and treatment of oral mucositis induced by cancer therapy. Meta-analysis was done, and all results are provided.

Databases searched were Medline, EMBASE, CINAHL, PedRo, and Cochrane Controlled Trial Register. Hand searching in physiotherapy and medical journals from several countries also were used.

Search keywords were low level laser therapy, low intensity laser therapy, low energy laser therapy, phototherapy, oral mucositis, cancer, chemotherapy, radiation therapy, and specific laser types.

Studies were included if they

• Involved patients with cancer who had been diagnoses with oral mucositis after chemotherapy or radiation therapy.
• Used treatment with laser therapy with wavelengths of 632–1064 nm.
• Incorporated a randomized parallel group or crossover design, with blinding and placebo control with identical placebo laser.

A total of 149 papers were initially retrieved. Literature was evaluated using the Jadad checklist and inclusion of study funding sources.

A final sample of 11 trials published from 1997–2009 included 415 patients. Samples ranged from 21–70 subjects and included those receiving chemotherapy, radiation therapy, combined therapy, and transplant cases. One study was done in children.

• Six trials involved prevention of OM. The overall effect size was 2.31 in favor of laser (p = 0.02). In one trial, which used less than 1 joule, results did not favor laser use. Subgroup analysis showed positive results with laser whether done before cancer therapy, before and during therapy, or during therapy.
• Five trials assessed duration of OM. Overall effect size was 8.35 in favor of laser therapy (p < 0.00001).
• Seven trials assessed severity of OM. Overall effect size was 4.01 in favor of laser (p < 0.00001). Subgroup analysis showed there was no significant difference in these findings with different wavelengths of infrared LLLT.
• Three trials studied the effect on pain. Effect size was 4.97 in favor of laser (p < 0.00001).
• All analyses showed substantial heterogeneity. LLLT was well tolerated with no serious incidents or withdrawals because of the LLLT treatment.

Moderate to strong evidence was found for effectiveness of LLLT in the prevention of OM, reduced duration and severity of OM, and reduced pain with doses of 1–6 joules per point. Trials aimed at prevention started LLLT seven days before cancer treatment regimens, and effective dosing seen ranged from 1–6 joules. This meta-analysis supported the effectiveness of LLLT in the dosage ranges reported here for the prevention and management of oral mucositis.

The quality of studies was determined to be high; however, substantial variation existed in the actual treatment procedures, number of treatments, timing of treatments, and heterogeneity in the overall findings.