Potential role of photobiomodulation as a prevention and treatment strategy for radiation induced fibrosis: a review of effectiveness and mechanisms

Abstract

Background: Radiation induced fibrosis (RIF) is a chronic progressive disabling side effect of radiation therapy in cancer survivors with limited therapeutic options. Photobiomodulation therapy (PBMT) is being propagated as a non-invasive therapeutic option but has limited evidence. This scoping review aims to summarize the effects and mechanisms of PBMT in the prevention and treatment of RIF.

Methods: A systematic search was conducted across five databases (PubMed, Scopus, EBSCO, ProQuest, LILACS), and three other platforms (Google Scholar, ResearchGate, Academia.edu). Retrieved studies underwent independent title, abstract, full text screening and data extraction. Quality analysis was performed for human studies to assess methodological rigor.

Results: The review identified three studies that specifically focused on RIF. Since induction of RIF is not common for in vitro and in vivo studies, the screening was expanded to include studies targeting fibroblast cells or fibrosis of any origin. The revised strategy led to inclusion of 26 studies (nine in vitro, 13 in vivo, and four clinical studies). Of these, 20 studies focused on the prevention of fibrosis, while six addressed its treatment. Preclinical studies demonstrated the beneficial effects of PBMT at different phases of fibrosis at cellular level. Clinical studies demonstrated functional improvements. Mechanisms include modulation of inflammatory pathways, fibroblast to myofibroblast conversion, collagen production, reduction of oxidative stress, and regulation of extracellular matrix remodeling.

Conclusion: PBMT demonstrates potential as a non-invasive, safe therapeutic option for RIF, supported by extensive preclinical evidence. However, high-quality clinical trials are necessary to validate its clinical efficacy.

Implication: PBMT offers a promising intervention for managing RIF, with potential to enhance body image, self-confidence, functional abilities, and overall quality of life for cancer survivors. This review underscores the need for further research to translate these findings into clinical practice.

Keywords: LED; Low level LASER therapy; Radiation fibrosis syndrome; Radiation therapy; Survivorship.

Figure 1. PRISMA flow diagram.

Figure 2. Schematic representation of PBMT usage across types of studies.

The fibrosis etiology, intervention and the number of in vitro studies (represented as fibroblast cell icon), in vivo studies (represented as a rodent icon) and clinical trials (represented as person icon). The orange circle represents fibrosis with radiation induced fibrosis (RIF) (represented as yellow circle) being the subset of fibrosis. The blue colored circle represents high level laser therapy (HLLT) while red colored circle represents photobiomodulation (PBMT).