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Photobiomodulation (PBM) reduces severity and duration of oral mucositis, and can be used for prevention.

The effect of Photobiomodulation (PBM Therapy) previously known as Low Level Laser Therapy (LLLT) on oral mucositis (by laser light) has been reported in 32 randomised controlled clinical trials. These includes patients undergoing chemotherapy, radiotherapy or haematopoietic stem cell transplantation (HSCT) in both pediatric and and adult populations. Most of the studies are therapeutic (treating symptoms) but some clinical trials have shown that treatment concurrent with cancer therapies can be preventative.


  • Oral mucositis

  • Hyposalivation and xerostomia

  • Lymphoedema


  • Radiation dermatitis


  • Dysphagia

  • Trismus

  • Fibrosis

  • Pain control

The progress of Photobiomodulation Therapy towards mainstream acceptance

  • 2019 - Multinational Association for Supportive Care in Cancer (MASCC) guidelines recommend PBM treatment for the prevention of oral mucositis. Click here

  • 2018 - National Institute of Health and Care Excellence (NICE) guidance for the UK NHS recommends laser therapy for oral mucositis. Click here

  • 2017 - UK NIHR funded RCT on the Clinical and Cost Effectiveness of Low Level Laser in the Management of Oral Mucositis in Head and Neck Cancer Irradiation, 10 NHS hospitals, 380 patients in progress. Click here

  • 2017 - Low Level Laser improves survival of head and neck cancer patients. Click here

What is PBM ?

Photobiomodulation (PBM) therapy, (previously known as Low Level Laser Therapy or LLLT) is the application of light to tissues to reduce inflammation and improve healing. It works by increasing cellular energy (ATP) and reducing free radicals (oxidative stress). There are over 700 randomised controlled clinical trials published on PBM for a wide range of painful and non healing applications including 32 controlled clinical trials on oral mucositis.

How PBM works

One of the main effects of PBM is on mitochondrial function: There are hundreds of different cell types in the body, each performing different functions, they all contain lots of mitochondria, (cellular power plants) which generate most of the cell's supply of energy (ATP). Mitochondria are also involved in a range of other cellular processes, including signalling, stem cell differentiation, inflammation, cell survival, apoptosis and are consequently implicated in many diseases.

Mitochondria in stressed or ischaemic tissues produce too much mitochondrial nitric oxide (mtNO) which binds to cytochrome c oxidase, competitively displacing oxygen and consequently reducing ATP, but this inhibition of mitochondrial respiration significantly increases production of ROS (free radicals). These excess ROS trigger the process of inflammation, cell death and subsequently oral mucositis.

Laser light of the correct wavelength (generated by low intensity lasers and LED's), when applied to stressed tissues, is absorbed by cytochrome c oxidase. The light displaces the mtNO thereby reducing oxidative stress and increasing ATP production; this reduces inflammation and increases cell metabolism. 

The subsequent cascade of downstream metabolic effects have been shown to include changes in gene transcription (NF-kB and AP-1), activation of latent TGF-β1, increased exchange of Ca2+, secretion of growth factors, activation of enzymes & many secondary messengers. 

Within hours (and sometimes minutes) following PBM, increases in cellular activity have been shown in vitro and in vivo in neutrophils, macrophages, fibroblasts, mast cells, endothelial cells and keratinocytes. Reduced inflammatory markers including prostaglandin E2, interleukin 1ß and TNFα have also been seen in many studies.

Clinical trials show a significant improvement in healing of wounds and reduction of pain. A recent systematic review on PBM for OM found that it reduces pain, severity and duration of chemotherapy and radiotherapy induced oral mucositis.

The Multinational Association of Supportive Care in Cancer (MASCC) now recommend PBM for the prevention of oral mucositis in adult patients receiving hematopoietic stem cell transplantation conditioned with high-dose chemotherapy. A new suggestion was made for low-level laser for the prevention of oral mucositis in patients undergoing radiotherapy, without concomitant chemotherapy, for head and neck cancer. 

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