Could the biological robustness of low level laser therapy (Photobiomodulation) impact its use in the management of mucositis in head and neck cancer patients

Current trends and available evidence on low-level laser therapy for osteoradionecrosis: A scoping review

BACKGROUND

This scoping review explored current trends and available evidence in Low-Level Laser Therapy (LLLT) in the treatment and prevention of osteoradionecrosis.

METHODS

The search strategy was conducted in MEDLINE/PubMed, EMBASE, Web of Science, and grey literature on January 15, 2024, without language or time restrictions.

RESULTS

19 studies were included. The application of LLLT protocols was 58% for therapeutic use, 21% for preventive use, and 21% for a combination of both. Regarding the use of antimicrobial photodynamic therapy (aPDT), 41% of the studies employed this technique, which utilized methylene blue as the photosensitizer. For treatments associated with photobiomodulation, 57% reported pharmacological treatment, 29% surgical treatment, 11% prescribed chlorhexidine mouthwashes, and 4% other therapies. In vivo studies used diode lasers emitting low incident power densities in the near-infrared wavelength (67%) at 780 to 904 nm. In comparison, case reports also used diode lasers emitting low incident power densities in the red and near-infrared wavelength (64%) at 660 to 904 nm. The continuous emission mode was utilized in 83% of in vivo studies and 17% of the case reports. None of the studies included in this review reported all laser parameters.

CONCLUSIONS

In general, studies suggested that LLLT can be used for therapeutic and preventive applications in the management of osteoradionecrosis. However, clinical studies are case reports and the variability in laser parameters across the included studies poses challenges for establishing standardized treatment protocols. The lack of comprehensive data on laser parameters underscores the need for future research to focus on standardizing LLLT protocols and conducting well-designed, large-scale clinical trials. This approach will help to better evaluate the effectiveness of LLLT and potentially integrate it more reliably into clinical practice.

High-power laser photobiomodulation therapy for immediate pain relief of refractory oral mucositis

PURPOSE

We aimed to evaluate the efficacy of high-power (class IV) laser photobiomodulation (PBM) therapy for immediate pain relief due to oral mucositis (OM) refractory to recommended first-line therapy.

METHODS

This retrospective study included 25 cancer patients with refractory chemotherapy- or radiotherapy-induced OM (16 and 9 patients, respectively) that were treated for pain relief with an intraoral InGaAsP diode laser (power density = 1.4 W/cm2). Pain was self-assessed immediately before and after laser treatment using a 0-to-10 numeric rating scale ([NRS], "0" = no pain, "10" = intolerable pain).

RESULTS

Patients reported an immediate decrease in pain following 94% (74 of 79) of the PBM sessions, in 61% (48 sessions) the pain reduction was over 50%, and in 35% (28 sessions) the initial pain was completely eliminated. There were no reports of increased pain post-PBM. For chemotherapy and radiotherapy-treated patients, mean reduction in pain NRS post-PBM was 4.8 ± 2.5 (p < 0.001) and 4.5 ± 2.8 (p = 0.001), indicating a post-PBM reduction of 72% and 60% of the initial pain level, respectively. The analgesic benefit of PBM remained for a mean of 6.0 ± 5.1 days. One patient reported a transient burning sensation after one PBM session.

CONCLUSIONS

High-power laser PBM may provide nonpharmacologic, patient-friendly, long-lasting, rapid pain relief for refractory OM.

Oral ulcer treatment using human tonsil-derived mesenchymal stem cells encapsulated in trimethyl chitosan hydrogel: an animal model study

BACKGROUND

Oral ulcers are a common side effect of chemotherapy and affect patients' quality of life. While stem cell transplantation is a potential treatment for oral ulcers, its efficacy is limited as the stem cells tend to remain in the affected area for a short time. This study aims to develop a treatment for oral ulcers by using trimethyl chitosan (TMC) hydrogel with human tonsil-derived stem cells (hTMSCs) to increase the therapeutic effect of stem cells and investigate their effectiveness.

METHODS

Animals were divided into four experimental groups: Control, TMC hydrogel, hTMSCs, and hTMSCs loaded in TMC hydrogel (Hydrogel + hTMSCs) (each n = 8). Oral ulcers were chemically induced by anesthetizing the rats followed by injection of dilute acetic acid in the right buccal mucosa. After confirming the presence of oral ulcers in the animals, a single subcutaneous injection of 100 µL of each treatment was applied to the ulcer area. Histological analyses were performed to measure inflammatory cells, oral mucosal thickness, and fibrosis levels. The expression level of inflammatory cytokines was also measured using RT-PCR to gauge therapeutic the effect.

RESULTS

The ulcer size was significantly reduced in the TMC hydrogel + hTMSCs group compared to the control group. The stem cells in the tissue were only observed until Day 3 in the hTMSCs treated group, while the injected stem cells in the TMC Hydrogel + hTMSCs group were still present until day 7. Cytokine analysis related to the inflammatory response in the tissue confirmed that the TMC Hydrogel + hTMSCs treated group demonstrated superior wound healing compared to other experimental groups.

CONCLUSION

This study has shown that the adhesion and viability of current stem cell therapies can be resolved by utilizing a hydrogel prepared with TMC and combining it with hTMSCs. The combined treatment can promote rapid healing of oral cavity wounds by enhancing anti-inflammatory effects and expediting wound healing. Therefore, hTMSC loaded in TMC hydrogel was the most effective wound-healing approach among all four treatment groups prolonging stem cell survival. However, further research is necessary to minimize the initial inflammatory response of biomaterials and assess the safety and long-term effects for potential clinical applications.

[Photobiomodulation in the prevention and the management of side effects of cancer treatments: Bases, results and perspectives]

BACKGROUND

Assess the current and potential indications of photobiomodulation (PBM) therapy and their level of evidence in the prevention or treatment of side effects related to oncology treatments (radiation therapy, and to a minimal extent favored and hematopoietic stem cell transplants). And report on the recommended modalities (parameters and doses) of PBM therapy.

MATERIALS AND METHODS

The Embase, Medline/PubMed, Cochrane, EBSCO, Scopus, and LILACS databases were systematically reviewed to include and analyze publications of clinical studies that evaluated PBM in the prevention or management side effects related to cancer treatments. The keywords used were "photobiomodulation"; "low level laser therapy"; "acute oral mucositis"; "acute dysphagia"; "acute radiation dermatitis"; "lymphedema"; "xerostomia"; "dysgeusia"; "hyposalivation"; "lockjaw"; "bone necrosis"; "osteoradionecrosis"; "radiation induced fibrosis"; "voice and speech alterations"; "palmar-plantar erythrodysesthesia"; "graft versus host disease"; "peripheral neuropathy"; "chemotherapy induced alopecia". Prospective studies were included, while retrospective cohorts and non-original articles were excluded from the analysis.

RESULTS

PBM in the red or infrared spectrum has been shown to be effective in randomized controlled trials in the prevention and management of certain complications related to radiotherapy, in particular acute mucositis, epitheliitis and upper limb lymphedema. The level of evidence associated with PBM was heterogeneous, but overall remained moderate. The main limitations were the diversity and the lack of precision of the treatment protocols which could compromise the efficiency and the reproducibility of the results of the PBM. For other effects related to chemo/radiation therapy (dysgeusia, osteonecrosis, peripheral neuropathy, alopecia, palmar-plantar erythrodysaesthesia) and haematopoietic stem cell transplantation (graft versus host disease), treatment with PBM suffers from a lack of studies or limited studies at the origin of a weakened level of proof. However, based on these results, it was possible to establish safe practice parameters and doses of PBM.

CONCLUSION

Published data suggest that PBM could therefore be considered as supportive care in its own right for patients treated with radiation, chemotherapy, immunotherapy, hormone therapy or targeted therapies, whether in clinical practice or clinical trials. therapies. However, until solid data have been published on its long-term safety, the use of PBM should be considered with caution and within the recommended parameters and doses, particularly when practiced in areas of known or possible tumours. In this case, the patient should be informed of the theoretical benefits and risks of PBM in order to obtain informed consent before treatment.

Photobiomodulation effects on fibroblasts and keratinocytes after ionizing radiation and bacterial stimulus

OBJECTIVE

Photobiomodulation therapy (PBMT) has proven to reduce inflammation and pain and increase wound healing. Thus, the aim of this study was to analyze the effects of PBMT parameters on migration, proliferation, and gene expression after ionizing radiation and bacterial-induced stress in an in vitro study.

DESIGN

Keratinocytes (HaCaT) and Fibroblasts (HGFs) were grown in DMEM with 10 % fetal bovine serum until stressful condition induction with lipopolysaccharide (LPS) of Escherichia coli (1 µg/mL), Porphyromonas gingivalis protein extract (5 µg/mL) and ionizing radiation (8 Gy). Low-laser irradiation (660 nm, 30 mW) was carried out in four sessions, with 6 h intervals, and energy density of 2, 3, 4, and 5 J/cm². Scratch assays, immunofluorescence, and RT-qPCR were performed.

RESULTS

Treated fibroblasts and keratinocytes showed significant response in proliferation and migration after scratch assays (p < 0.05). Higher expressions of α-SMA in fibroblasts and F-actin in keratinocytes were observed in cells subjected to 3 J/cm². PI3K-pathway genes expression tended to enhance in fibroblasts, presenting a higher relative expression when compared to keratinocytes. In keratinocytes, PBMT groups demonstrated deregulated expression for all inflammatory cytokines' genes tested while fibroblasts presented a tendency to enhance those genes expression in a dose dependent way.

CONCLUSIONS

The present study showed that delivering 660 nm, 30 mW was effective to stimulate cell migration, proliferation and to accelerate wound healing. PBMT can modulate cytokines and pathways involved in wound repair. The different energy densities delivering distinct responses in vitro highlights that understanding laser parameters is fundamental to improve treatment strategies.

Assessment of Integrative Therapeutic Methods for Improving the Quality of Life and Functioning in Cancer Patients-A Systematic Review

Background: Cancer rehabilitation represents a series of measures adopted for the recovery of psychological, emotional, social, and financial functioning in the case of cancer patients. The purpose of this study is to identify the main elements of therapeutic management in the field of medical rehabilitation, as well as integrative, complementary medicine and holistic approaches that can be performed on the oncological patient. Methods: This systematic literature review follows the methodology outlined in the "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" ("PRISMA") statement, which is an internationally recognized and widely accepted standard. Results: Active rehabilitative therapies offer therapeutic options for improving the functioning and quality of life of oncological patients; these therapies comprehensively address both the physical and psychological aspects of the disease. This review also includes the latest novelties and nanotechnologies applied in oncological rehabilitation, for example, drugs (or supplements) inspired by nature. Conclusions: Physical and rehabilitation medicine, mostly using stimulating therapeutic methods, was recently added to the list of contraindications in the management of oncological patients, both as an approach to the pathological concept itself and as an approach to the main clinical consequences and functional aspects of oncological therapies. Integrative, complementary medicine presents an important therapeutic resource in the case of oncological patients. Advanced studies are needed in the future to further ascertain the role of these therapies.

Mechanism of action of photobiomodulation with light-emitting diode on the glutamine-dependent CT26 cell

We investigated the mechanism of action of photobiomodulation (PBM) with light-emitting diode (led) 640 nm of glutamine-dependent CT26 cells. Cells were exposed to 0.147-10.979 mW/cm2 of 640 ± 15 nm laser light for 15 min/day for 10 days. Cell proliferation and apoptosis were detected by MTT (3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-diphenytetrazoliumromide) and annexin V-FITC assays. mRNA and protein levels of cell proliferation-related genes were measured by RT-PCR and western blotting, respectively. With Gln 7.94 mM, on Day 8 and 10, genes GLUT1, MEK1, ERK2, BCL2, E2F1, HO-1, Ctnnb1, and Per2 was significantly upregulated (p < 0.01) of glutamine addiction. In PBM therapy, compared with the non-illuminated group, 2.17 mW/cm2 can significantly reduce cell apoptosis, the mRNA level of gene mTOR1 was significantly upregulated, and the protein level of raptor of GLUT1 and mTOR1, MEK1/2, and ERK1/2 were upregulated. LED 640 nm inhibits cell apoptosis without increasing cell proliferation by regulating GLUT1, MEK/ERK, and PI3K/AKT/mTOR signals.

Bibliometric Analysis to Global Research Status Quo on Photobiomodulation

Background: Photobiomodulation (PBM) becomes a remedial technology with growing popularity. The primary goal of this article is to conduct a PBM literature review, providing an overall systematic understanding of current and future trends. Methods: A dataset was made with topic retrieval, concerning PBM research retrieved from the Web of Science Core Collection. We analyzed to forecast research frontiers in this field using the softwares: VOSviewer, CiteSpace, and Biblioshiny. Results: Four thousand five hundred thirty pieces of literature were retrieved from our database. Current trends were characterized by keywords of "light," "spinal cord injury," "skeletal muscle," and so on. Future trends were characterized probably by six cutting-edge terms: "wound healing," "pain," "oral mucositis," "Alzheimer's disease," "Parkinson's disease," and "orthodontics." Conclusions: This study finds that the inadequacy of in-depth reliable interpretation of current clinical data calls for molecular biological mechanisms together with well-designed, large-sample, multicenter clinical trials. The study of oral, wound, and neural-related mechanisms and the exploration of therapeutic effects may be the popular trend at present and in the next few years.

Photobiomodulation enhances M2 macrophage polarization properties of tonsil-derived mesenchymal stem cells

In this study, the effect of photobiomodulation (PBM) treatment using 630 nm light emitting diode (LED) array (continuous wave type, 10 mW power) on tonsil-derived mesenchymal stem cells (TMSCs) and its interaction with RAW 264.7 macrophage cells via co-culture in vitro were investigated. PBM treatment was used as a priming method for TMSCs to improve therapeutic efficacy. TMSCs were subjected to multi-dose PBM treatments before co-culture with M1 activated (1 μg/mL lipopolysaccharide, LPS) macrophage cells with total energy doses of 0, 15, 30, and 60 J. Irradiation set at 15 J (1500 s treatment time) was performed once, twice for 30 J, and four times for 60 J in an incubator kept at 37 °C and 5% CO2. No significant anti-inflammatory response was observed for TMSCs co-cultured with macrophage cells without PBM. But PBM treatment of TMSCs with 630 nm LED array at 30 J reduced expression of inducible nitric oxide synthase, iNOS (M1) and increased expression of Arginase-1, Arg-1 (M2) phenotype macrophage markers. Anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) gene expression also increased significantly. Based on the results, PBM priming of TMSCs supports M2 macrophage polarization. PBM can be used to improve the therapeutic efficacy of TMSCs for potential applications in oral mucositis and wound healing.

A randomized, controlled trial to investigate cognitive behavioral therapy in prevention and treatment of acute oral mucositis in patients with locoregional advanced nasopharyngeal carcinoma undergoing chemoradiotherapy

Purpose

Oral mucositis is a common side effect of concurrent chemoradiotherapy (CCRT). This study aimed to determine whether cognitive behavioral therapy (CBT) could help prevent oral mucositis during chemoradiation therapy for locoregional advanced nasopharyngeal carcinoma (LA-NPC).

Methods and materials

Between July 15, 2020, and January 31, 2022, a randomized controlled phase II trial was conducted. Eligible patients (N=282, 18-70 years old) with pathologically diagnosed LA-NPC were randomly assigned to receive CBT or treatment as usual (TAU) during CCRT (computer-block randomization, 1:1). The primary endpoints were the incidence and latency of oral mucositis.

Results

The incidence of oral mucositis was significantly lower in the CBT group (84.8%; 95% confidence interval [CI], 78.7%-90.9%) than in the TAU group (98.6%; 95% CI, 96.6%-100%; P<0.001). The median latency period was 26 days and 15 days in the CBT and TAU groups, respectively (hazard ratio, 0.16; 95% CI, 0.12-0.22; P<0.001). CBT significantly reduced ≥ grade 3 oral mucositis (71.9% vs. 22.5%, P<0.001), dry mouth (10.8% vs. 3.7%, P=0.021), dysphagia (18% vs. 5.1%, P=0.001), and oral pain (10% vs. 3.6%, P=0.034) compared with TAU. Patients receiving CBT and TAU during CCRT had similar short-term response rates.

Conclusions

CBT reduced the occurrence, latency, and severity of oral mucositis in patients with LA-NPC during CCRT.

Quality assessment of PBM protocols for oral complications in head and neck cancer patients: part 2

PURPOSE

To investigate the role of photobiomodulation (PBM) in patients undergoing head and neck cancer (HNC) treatment. We focused on the consequences of the main complications, such as quality of life (QoL), analgesia, functional impairment, and nutritional status, as well as on the impact on survival/ recurrences, radiotherapy (RT) interruption, adherence, cost-effectiveness, safety, feasibility, and tolerability.

METHODS

An electronic search in PubMed and Scopus databases was performed. Full texts were carefully assessed, and data were assimilated into a tabular form for discussion and consensus among the expert panel.

RESULTS

A total of 22 papers were included. Overall, a beneficial effect of PBM was evidenced in the amelioration of QoL, nutritional status, the reduction of pain, and functional impairment. Preventive PBM may reduce the incidence and duration of RT interruptions, potentially contributing to improved cancer treatment outcomes. PBM treatments are safe and recommended for routine use, with the caveat of avoiding direct tumor exposures where feasible. However, it does not appear to impact cancer survivorship/recurrences directly. Despite additional clinical efforts involving routine PBM use, the individual and public health benefits will positively impact oncology care.

CONCLUSIONS

Quality of life, pain and functional impairment, nutritional status, and survival may be effectively improved with PBM. Given its established efficacy also in reducing RT interruptions and its safety, feasibility, and tolerability, PBM should be included in the field of supportive cancer care in HNC patients. Improved understanding of PBM mechanisms and precise dose parameters is enabling the generation of more robust, safe, and reproducible protocols; thus, it is imperative to support further clinical implementation as well as both applied and basic science research in this novel field.

Possible adverse effects of low-level laser on oral and oropharyngeal cancer cells: A scope review

BACKGROUND

The effects of laser therapy on normal cells are well known and accepted, but the impact of this therapy on malignant cells are not yet fully understood. This review aims to map and outline what the scientific literature addresses on the effects of laser therapy on malignant cells.

METHODS

This review article followed the guidelines of the PRISMA-ScR protocol, being all the search, analysis, and selection of articles based on it.

RESULTS

After all application of the predetermined criteria, five studies were included, dated between the years 2013 and 2021. With the complete reading of the selected studies, 100% of the articles were classified as category III of the Agency for Healthcare as Research and Quality classification. Similar themes among the papers included were investigated and compared. In these five studies, the visible red and near infrared wavelengths were used, and energy densities varied between 1 and 5 J/cm² . It was observed that low-level laser could alter the expression of cell proliferation and migration proteins, such as cyclin D1, E-cadherin, and β-catenin. In addition, changes related to increased cell viability and metabolism were also identified.

CONCLUSION

The low-level laser seems to positively regulate the proliferative, migratory, and viability capacity of neoplastic cells, depending on the protocol used. All these studies included in the review are equivalent to in vitro studies; the cells are not in such a complex environment as is an organized tissue, making it necessary to carry out more complex tests, such as in vivo research.

Can transcranial photobiomodulation improve cognitive function? A systematic review of human studies

BACKGROUND

Transcranial photobiomodulation (tPBM) has been studied for over a decade as a possible cognitive intervention.

OBJECTIVE

To evaluate the effect of tPBM for enhancing human cognitive function in healthy adults and remediating impaired cognitive function in adults with cognitive disorders.

METHODS

A systematic literature search from three electronic databases (PubMed, Scopus, Web of Science) was conducted from 1987 to May 2022. The cognitive function being evaluated included learning and memory, attention, executive function, language, and global cognitive function.

RESULTS

Of the 35 studies identified, 29 (82.9 %) studies reported positive improvement in cognitive functions after tPBM. All nine studies on participants with subjective memory complaints, mild cognitive impairment, and dementia, showed positive outcomes. Seven (87.5 %) studies on traumatic brain injury (TBI) patients also showed positive results. A series of clinical trials on stroke patients showed positive trends on improved neurological deficit at first, but was prematurely terminated later at phase III due to the lack of statistical significance. One of the most common protocols for clinical populations employed devices delivering near-infrared light (810 nm), the irradiance of 20-25 mW/cm², and fluence of 1-10 J/cm². While this was common, the reviewed protocols also included other wavelengths of light ranging from visible, red (630-635 nm) to invisible near-infrared maximum wavelengths of 1060-1068 nm.

CONCLUSIONS

tPBM seems to improve cognitive function. However, only half of the reviewed clinical trials were randomized control trials, further investigation is warranted.

Transcutaneous Electrical Stimulation, Interferential Current and Photobiomodulation May Lead to the Recurrence of Breast Cancer in Rats?

Introduction: Transcutaneous electrical nerve stimulation (TENS), interferential current therapy (IFC) and photobiomodulation therapy (PBMT) have been used in the management of cancer-related pain in adults. However, there are still some controversy regarding the effects of this therapy on tumor cells that may remain after cancer treatment. Objective: To evaluate the risk of recurrence of breast cancer in rats when using TENS, IFC or PBMT. Method: An experimental, randomized, controlled and cross-sectional study. With 90 days of age, 7,12-dimetylbenz(a)anthracene (7,12-DMBA) was administered to rats by gastric gavage to induce mammary cancer. After 120 days the mammary glands of the rats belonging to the group with mammary cancer were removed. Results: 39 female Sprague-Dawley rats were studied: 9 rats without induction of mammary carcinoma; 9 rats with induction of mammary carcinoma and without surgery; 9 rats with induction of mammary carcinoma with surgery and placebo application of TENS, IFC, PBMT; 9 rats with induction of mammary carcinoma, surgery and the application of TENS, IFC and PBMT. Conclusion: This study demonstrated that there was local recurrence of tumors in rats that were stimulated with TENS or IFC, however no evidence of local recurrence with PBMT.

Efficacy and safety of thalidomide in preventing oral mucositis in patients with nasopharyngeal carcinoma undergoing concurrent chemoradiotherapy: A multicenter, open-label, randomized controlled trial

BACKGROUND

This multicenter clinical trial was designed to evaluate the efficacy and safety of thalidomide (THD) in preventing oral mucositis (OM) in patients with nasopharyngeal carcinoma (NPC) undergoing concurrent chemoradiotherapy (CCRT).

METHODS

Patients with locally advanced NPC were randomly assigned to either a THD group or a control group. All 160 patients received radical intensity-modulated radiotherapy plus cisplatin-based concurrent chemotherapy and basic oral hygiene guidance. Patients in the THD group received additional THD at the beginning of CCRT. The primary end points were the latency period and the incidence of OM. The secondary end points were mouth and throat soreness (MTS), weight loss, short-term efficacy, and adverse events.

RESULTS

The median latency period of OM was 30 and 14 days in the THD and control groups, respectively (hazard ratio, 0.32; 95% confidence interval, 0.23-0.35; P < .0001). The incidence of OM and severe OM (World Health Organization grade 3 or higher) was significantly lower in the THD group than the control group (87.5% vs 97.5% [P = .016] and 27.5% vs 46.3% [P = .014], respectively). THD treatment also remarkably reduced the intensity of MTS and the degree of weight loss. In comparison with the control group, the incidence of nausea, vomiting, and insomnia was significantly decreased, whereas the incidence of dizziness and constipation was obviously increased in the THD group. The objective response rates 3 months after CCRT were similar between the groups.

CONCLUSIONS

THD prolonged the latency period, reduced the incidence of OM, and did not affect the short-term efficacy of CCRT in patients with NPC.

LAY SUMMARY

Oral mucositis is the most common complication of nasopharyngeal carcinoma during chemoradiotherapy; it decreases the patient's quality of life, and ideal mucosal protective agents are lacking. A few basic research and preclinical studies have shown that thalidomide may be an approach to ameliorating oral mucositis. The results of the current study confirm that thalidomide has a protective effect against oral mucositis in patients who have received chemoradiotherapy for nasopharyngeal carcinoma.

808-nm Photobiomodulation Affects the Viability of a Head and Neck Squamous Carcinoma Cellular Model, Acting on Energy Metabolism and Oxidative Stress Production

Photobiomodulation (PBM) is a form of low-dose light therapy that acts through energy delivery from non-ionizing sources. During the recent two decades, there has been tremendous progress with PBM acceptance in medicine. However, PBM effects on potential stimulation of existing malignant or pre-malignant cells remain unknown. Thus, the primary endpoint was to assess the safety of PBM treatment parameters on head and neck squamous cell carcinoma (HNSCC) proliferation or survival. The secondary endpoint was to assess any putative anti-cancer effects of PBM treatments. Cell viability, energy metabolism, oxidative stress, and pro- and anti-apoptotic markers expression were investigated on a Human Head and Neck Squamous Cell Carcinoma cellular model (OHSU-974 FAcorr cell line). PBM therapy was administered through the 810 nm diode laser (GaAlAs) device (Garda Laser, 7024 Negrar, Verona, Italy) at the powers of 0, 0.25, 0.50, 0.75, 1.00, or 1.25 W in continuous wave (CW) mode for an exposure time of 60 s with a spot-size of 1 cm² and with a distance of 1.86 cm from the cells. Results showed that 810-nm PBM affected oxidative phosphorylation in OHSU-971 FAcorr, causing a metabolic switch to anaerobic glycolysis. In addition, PBM reduced the catalase activity, determining an unbalance between oxidative stress production and the antioxidant defenses, which could stimulate the pro-apoptotic cellular pathways. Our data, at the parameters investigated, suggest the safeness of PBM as a supportive cancer therapy. Pre-clinical and clinical studies are necessary to confirm the in vitro evidence.

Effect of Radiotherapy and Low-Level Laser Therapy on Circulating Blood Cells of Rats

Introduction: This study aimed to investigate the effect of low-level laser therapy (LLLT) on the blood cell count when applied to parotid glands of rats irradiated by volumetric modular arc therapy (VMAT). Methods: Thirty-two adult male Wistar rats were used in this study. Samples were randomly assigned to three groups: control group (CG, n = 8), immediate laser group (24 hours) (ILG, n=12), and late laser group (120 hours) (LLG, n=12). The two laser groups were previously subjected to VMAT radiotherapy in a single dose of 12 Gy. LLLT with an AsGaAl laser (660 nm, 100 mW) was applied at three points in the region of the parotid glands, right side, with the energy of 2 J per point (20s, 70 J/cm²) and a spot size of 0.0028 cm² for 10 consecutive days. In the euthanasia, blood samples were obtained by cardiac puncture. The samples from each group were processed by an automatic method and analyzed for erythrogram, leukogram and platelet count values. The data were analyzed by ANOVA and each LLLT time point was analyzed in relation to the control group, with a significance level less than 0.05. Results: Groups using LLLT had higher red blood cell counts, being higher in the LLG (P = 0.000). The hematimetric indices MCV (P = 0.002) and MCH (P = 0.009) were lower than the control group, especially when compared to the group using LLLT 120h after radiotherapy (LLG). White blood cell counts were lower in the groups with radiotherapy and immediate use of LLLT (ILG) (P = 0.011), mainly at the expense of lymphocytes (P = 0.002). Conclusion: The results suggest a potential systemic effect of LLLT, especially on circulating red blood cell counts, regardless of their time of immediate or late use of radiotherapy.

Extraoral photobiomodulation for prevention of oral and oropharyngeal mucositis in head and neck cancer patients: interim analysis of a randomized, double-blind, clinical trial

Purpose

To assess the safety and efficacy of prophylactic extraoral photobiomodulation (PBM) for the prevention of oral and oropharyngeal mucositis (OM) on clinical outcomes and survival in patients with oral cavity and oropharyngeal squamous cell carcinoma (OOPSCC).

Methods

OOPSCC patients who received radiotherapy (RT) were prospectively randomized to two groups: prophylactic extraoral PBM and placebo. OM grade (NCI), pain (VAS), analgesia, and anti-inflammatory prescriptions were assessed weekly. Quality of life questionnaires (QoL) were performed at the first and last day of RT. Following RT, participants were evaluated quarterly for oncological outcomes follow-up.

Results

Fifty-five patients met the inclusion criteria. The first occurrence of OM was observed at week 1, for the placebo group (p = 0.014). Later, OM onset and severity was observed for the PBM group, with first occurrence at week 2 (p = 0.009). No difference in severe OM incidence was observed (p > 0.05). Lower mean pain score was noted at week 7 for the PBM group (2.1) compared to placebo group (4.5) (p = 0.009). Less analgesics (week 3; p = 0.009/week 7; p = 0.02) and anti-inflammatory prescription (week 5; p = 0.0346) were observed for the PBM group. Better QoL scores were observed for the PBM group at last day of RT (p = 0.0034). No difference in overall survival among groups was observed in 1 year of follow-up (p = 0.889).

Conclusion

Prophylactic extraoral PBM can delay OM onset, reduce pain, and reduce analgesic and anti-inflammatory prescription requirements. Extraoral PBM was associated with better QoL. There was no evidence of PBM impact on oncological outcomes.

Trial registration

TRN:RBR-4w4swx (date of registration: 01/20/2020).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-021-06625-8.

Treatment Parameters of Photobiomodulation in the Prevention of Non-surgical Cancer Treatment-Induced Oral Mucositis: A Review of Preclinical Studies

Introduction: The most important side effect after non-surgery cancer treatment (NSCT) is oral mucositis (OM) which degrades the quality of life. Using photobiomodulation (PBM), formerly known as low-level laser therapy (LLLT), in the prevention of NSCT-induced OM was widely studied. Hence, this review evaluates the efficacy of optical treatment parameters behind the working process of PBM in preventing NSCT-induced OM in preclinical studies. Methods: Using the PubMed, Scopus and Embase databases, the present study systematically reviewed existing preclinical studies for optical treatment parameters of PBM in preventing NSCT-induced OM in experimental models without restriction on the year of publication. Results: In total, 51 articles were recognized during the search of the literature, and only 16 research papers were included in this review, taking into consideration the inclusion as well as exclusion benchmarks. The reviewed studies showed that a consensus has yet to be reached on the optimal PBM treatment parameters in preventing NSCT-induced OM. However, a wavelength of 660 nm, a power density of 40 mW as well as fluence which ranged between 2 and 6 J/cm2 were mostly utilized in the included studies. Furthermore, the severity of NSCT-induced OM was reduced following PBM application with no reported severe side effects. Conclusion: The efficacy of PBM with the associated optical parameters is a promising strategy in preventing NSCT-induced OM. However, the optimal parameters of PBM need to be investigated.

[State of art of photobiomodulation in the management of radiotherapy adverse events: Indications and level of evidence]

PURPOSE

To evaluate the current and potential indications of photobiomodulation (PBM) and their level of evidence in the prevention or management of radiation therapy-related side effects.

MATERIALS AND METHODS

The Embase, Medline/PubMed, Cochrane, EBSCO, Scopus, and LILACS databases were systematically reviewed to include and analyze publications of clinical studies that have assessed PBM in the prevention or management of radiotherapy-related side effects. The keywords used were "photobiomodulation"; "low level laser therapy"; "acute oral mucositis"; "acute dysphagia"; "acute radiation dermatitis"; "lymphedema"; "xerostomia"; "hyposalivation"; "trismus"; "bone necrosis"; "osteoradionecrosis"; and "radiation induced fibrosis". Prospective studies were included, whereas retrospective cohorts and non-original articles were excluded from the analysis.

RESULTS

PBM in the red or infrared spectrum has demonstrated efficacy in randomized controlled trials in the prevention and management of radiotherapy-related side effects, especially acute oral mucositis, acute radiation dermatitis, and upper extremity lymphedema. The level of evidence associated with PBM was heterogeneous, but overall was still moderate. The main shortcomings were the diversity and lack of detail in treatment protocols, which could have compromised efficiency and reproducibility of PBM results.

CONCLUSION

The published data suggest that PBM may be considered as a full-fledged supportive care for patients treated with radiotherapy, or at least in the setting of a therapeutic clinical trial. However, until strong evidence has been published on its long-term safety, the use of PBM should be considered with caution, specifically when applied near areas with proven or potential tumors. The patient should be informed of the theoretical benefits and risks of PBM in order to obtain his informed consent before treatment.

Long-term safety of photobiomodulation therapy for oral mucositis in hematopoietic cell transplantation patients: a 15-year retrospective study

Photobiomodulation therapy (PBMT) has demonstrated efficacy in the prevention and treatment of oral mucositis (OM) in hematopoietic cell transplantation (HCT). However, based on the cell stimulation properties, its long-term safety has been questioned, mainly in relation to risk for secondary malignancies in the oral cavity. The aim of this study was to investigate if different PBMT protocols for OM control have association with immediate and late adverse effects in HCT patients. Data on autologous and allogeneic transplantation, conditioning regimen, PBMT protocols, and OM severity were retrospectively collected from medical and dental records. Presence of secondary malignancies in the oral cavity was surveyed during a 15-year follow-up. Impact of OM on overall survival was also analyzed. Different PBMT protocols for prevention and treatment of OM were recorded over the years. Severe OM (grades 3 and 4) was infrequently observed. When present, we observed a significant decrease of the overall survival. No immediate adverse effect and secondary malignancy was associated to PBMT. In conclusion, the PBMT protocols used in the study were considered safe. The low frequency of severe OM observed encourages the implementation of this technique, with a special emphasis on the dosimetry adjustments focused on the HCT context.

Mechanisms of PhotoBioModulation (PBM) focused on oral mucositis prevention and treatment: a scoping review

Background

Oral mucositis (OM) is a severe complication cancer patients undergo when treated with chemoradiotherapy. Photobiomodulation (PBM) therapy also known as low-level laser therapy has been increasingly used for the treatment of such oral toxicity. The aim of this review is to discuss the mechanisms of photobiomodulation (PBM) regarding OM prevention and treatment, and more precisely to focus on the effect of PBM on tumor and healthy cells.

Methods

MEDLINE/PubMed, and google scholar were searched electronically. Selected studies were focusing on PBM effects on tumor and healthy cells.

Results

PBM interactions with the tissue and additional mechanism in OM therapy were detailed in this review. Moreover, this review highlighted a controversy about the carcinogenic effect of PBM. Indeed, Many studies reported that PBM could enhance malignant cell proliferation; suggesting that PBM would have no protective effect. In addition to acting on cancer cells, PBM may damage healthy cells.

Conclusion

More prospective studies are needed to assess the effect of PBM on cancer cells in order to improve its use for OM prevention and treatment.

Photobiomodulation exerts anti-inflammatory effects on the vascular and cellular phases of experimental inflammatory models

Photobiomodulation therapy (PBMT) is a non-thermal therapeutic procedure widely used in clinical practice. It is considered an effective modality of treatment for the control of various inflammatory conditions with fewer adverse effects as compared to conventional therapy. However, despite the clinical effects, the mechanisms of action and dosimetric parameters of PBMT are not fully understood. This study was performed to describe the effects of two different doses of PBMT on experimental models of inflammation. Male Swiss mice were administered with 0.9% of saline or phlogistic agents (carrageenan, dextran, serotonin, histamine, or bradykinin) by intra-plantar injection and were treated with PBMT at a dose of 1 or 5 J/cm²; right after, the variation of the paw volume was made, and histopathological analysis and myeloperoxidase assay of the carrageenan-induced edematous paw tissues were performed. The action of PBMT on carrageenan-induced vascular permeability was further evaluated. Our results showed that PBMT (1 J/cm²) led to an improvement in paw edema induced by the phlogistic agents and further reduced the histological scores. Inhibition of neutrophil migration was observed following the administration of 1 and 5 J/cm² of PBMT. However, only 1 J/cm² of PBMT showed beneficial effects on carrageenan-induced edema. Laser at a dose of 1 J/cm² showed cellular and vascular effects since it was able to reverse all the inflammatory parameters, and laser at a dose of 5 J/cm² probably has only cellular effects in the presence of acute inflammation.

Successful GaAlAs low-level laser therapy of self-inflicted thermal burns of the palate

Thermal burns of the oral cavity usually arise from ingestion of hot foods or beverages. A 38-year-old female patient presented with two painful ulcerative erythematous patches of the palate. The patient was consulted on the same day lesions appeared. Medical history was unremarkable. Clinically significant self-inflicted injuries may result in wide ulcers in the mouth and usually do not take less than 2 weeks to heal, whereas our patient, treated with low-level laser therapy, had a complete response in day 4, after 2 days of treatment. The fact that multiple lesions were present signaled against the World Health Organization exclusion diagnosis of erythroplakia for red patches. A traumatic ulcer, regardless of its cause of origin, usually heals within 2 weeks, after the source of injury is resolved. A thermal burn in the oral cavity usually takes longer than that to heal, but whenever this time frame is not respected, the suspicion of a potentially malignant disorder should always arise, and a biopsy should be performed. The present case showed two painful thermal burns with great results in terms of speeding up the relieve of symptoms and healing time with soft laser as opposed to the traditional treatment with oral topical corticosteroid.

Treatment for Oral Mucositis-Current Options and an Update of Small Molecules Under Development

OPINION STATEMENT

Despite its history as one of the most impactful toxicities associated with cytotoxic cancer therapy, oral mucositis (OM) remains an unmet clinical need which affects hundreds of thousands of patients. Descriptions of its complex pathogenesis have provided mechanistic targets which are being exploited to develop an effective therapeutic intervention. Favorable results of recently completed clinical trials in which agents focused on interrupting the early stages of the mucositis biological cascade were assessed provide reason for optimism, not only for oral mucositis but also for halo indications which share its pathobiogenesis.

Photobiomodulation (low-level laser) therapy for immediate pain relief of persistent oral ulcers in chronic graft-versus-host disease

PURPOSE

To determine the immediate pain-relieving effect of photobiomodulation therapy (PBMt) in patients with oral ulcers of chronic graft-versus-host disease (cGVHD) refractory to first line therapy with topical corticosteroids.

METHODS

This retrospective study included all patients who underwent PBMt for pain relief of refractory oral cGVHD lesions. PBMt was applied using an intraoral approach to all sites with mucosal lesions, using a 940 nm InGaAsP diode laser device, with the following parameters: pulsed modulation (duty cycle of 50%), power 0.7 W, illuminated spot size 7.1 cm², irradiance 98.6 mW/cm², and irradiation time 90 s per point. Pain was self-assessed using a 0-to-10 scale immediately before and after PBMt.

RESULTS

Data from eleven patients with a total of 56 PBMt sessions were analyzed. In 48 (85.7%) sessions, the patients reported less pain immediately after treatment, with a reduction of ≥ 50% of the initial pain level in 43 (76.8%) sessions. Mean pre- and post-treatment pain levels were 5.20 ±2.7 and 1.38 ±2.1, respectively (p < 0.001), i.e., a post-treatment reduction of 73.4% of the initial pain level. The benefits of the treatment remained for a mean of 6.50 ±5.4 days (range of 2 to 14 days). No adverse effects were reported.

CONCLUSIONS

PBMt seems to be a promising treatment modality for refractory oral cGVHD lesions as a rapid pain reliever with relatively long-lasting effects.

Effects of 660 nm and 810 nm Low-Power Diode Laser on Proliferation and Invasion of Oral Cancer Cells in Cell Culture Media

In the present study, the effects of 660 and 810 nm diode laser on the proliferation and invasion of cancer cells were investigated. Sixteen plates of oral cancer cells originated from tongue SCC were irradiated with diode laser at 660 nm (40 and 80 mW) and 810 nm (100 and 200 mW) with the energy density of 4 J cm^-2 . One plate received no irradiation (the control). Irradiation was performed at four times (0, 24, 72 and 168 h). Cell proliferation was measured by MTT assay. The Ki67 and vascular endothelial growth factor (VEGF) markers were examined by real-time polymerase chain reaction (RT-PCR). Cyclin D1, E-cadherin, β-catenin and matrix metalloproteinase-9 (MMP-9; flow cytometry) were also evaluated. Proliferation was lower in the irradiated groups. This result was significant for all groups at 24 h. The percentages of cyclin D1 and MMP-9 were higher in 810 nm groups, β-catenin and E-cadherin were higher in 660 nm groups, VEGF marker was significantly lower in 810 nm/200 mW group, and Ki67 marker has no difference between the groups. According to the results of this study, laser irradiation at 0 and 24 h resulted in a significant inhibitory effect on cell proliferation especially in 660 nm/80 mW and 810 nm/200 mW. Further studies are needed in this respect.

Effect of Photodynamic Therapy on Cyclin D1 and P53 mRNA Levels in Head and Neck Squamous Cell Carcinoma Cell Line

Background: Photodynamic Therapy (PDT) is considered as one of the alternative treatments for Head and Neck Squamous Cell Carcinoma (HNSCC). P53 mRNA is a tumor suppressor gene whose mutation increases the likelihood of uncontrolled cancer-like divisions. The mutation of CCND1 oncogenic increases the production of cyclin D1 as a tumorigenic protein. Objectives: This study aimed to determine the effect of PDT using toluidine blue as a photosensitizer on the CCND1 and P53 mRNA levels in the HNSCC cell line. Methods: A human HNSCC cell line from NCBI.C196 designation HN5 was used. Cells were divided into four groups: Group I (HNSCC cell line under the influence of toluidine blue and laser irradiation), group II (HNSCC cell line under the influence of toluidine blue), group III (HNSCC cell line under laser irradiation), group IV (control group, HNSCC cell line). A 660 nm THOR laser using toluidine blue as a photosensitizer was applied. The RNA extraction was performed in three steps, including cell degradation, purification, and precipitation by alcohol. The cDNA was prepared using Takara Kit. The Amplicon kit and Real-Time PCR analysis were used for the assessment of mRNA relative levels. Results: The P53 mRNA relative levels were 1.50 ± 0.33 in group I (P = 0.65), 1.49 ± 0.23 (P =0.5) in group II, and 1.40 ± 1.05 (P = 0.63) in group III. Compared to the control group, the mean increases in CCND1 mRNA were 18.01 ± 3.37 (p=0.04) in group I, 17.69 ± 3.3 (P = 0.03) in group II, and 9.01 ± 6.17 (P = 0.20) in group III. Conclusions: The comparison of the fold change index for P53 and CCND1 mRNA by the one-way ANOVA test showed that despite the increased expression of P53 and CCND1 mRNA in treatment groups compared to the control group, there was no statistically significant difference between the increases in P53 mRNA (P = 0.99) and CCND1 mRNA (P = 0.22) index between the groups. The results of this study could be a starting point for a better understanding of the mechanism of genes in PDT of the HNSCC cell line.

Oral mucositis: the hidden side of cancer therapy

Inflammation response of epithelial mucosa to chemo- radiotherapy cytotoxic effects leads to mucositis, a painful side effect of antineoplastic treatments. About 40% of the patients treated with chemotherapy develop mucositis; this percentage rises to about 90% for head and neck cancer patients (HNC) treated with both chemo- and radiotherapy. 19% of the latter will be hospitalized and will experience a delay in antineoplastic treatment for high-grade mucositis management, resulting in a reduction of the quality of life, a worse prognosis and an increase in patient management costs. Currently, several interventions and prevention guidelines are available, but their effectiveness is uncertain. This review comprehensively describes mucositis, debating the impact of standard chemo-radiotherapy and targeted therapy on mucositis development and pointing out the limits and the benefits of current mucositis treatment strategies and assessment guidelines. Moreover, the review critically examines the feasibility of the existing biomarkers to predict patient risk of developing oral mucositis and their role in early diagnosis. Despite the expression levels of some proteins involved in the inflammation response, such as TNF-α or IL-1β, partially correlate with mucositis process, their presence does not exclude others mucositis-independent inflammation events. This strongly suggests the need to discover biomarkers that specifically feature mucositis process development. Non-coding RNAs might hold this potential.

Salivary alpha-1-antitrypsin and macrophage migration inhibitory factor may be potential prognostic biomarkers for oncologic treatment-induced severe oral mucositis

AIMS

Evaluate the abundance of the selected targets, alpha-1-antitrypsin (A1AT) and macrophage migration inhibitory factor (MIF), and correlate these findings with the risk of developing severe oral mucositis (OM).

MATERIALS AND METHODS

Head and neck squamous cell carcinoma (HNSCC) patients submitted to radiotherapy (RT) or chemoradiotherapy (CRT) were assessed. OM grade and pain were evaluated daily during treatment. Two protein targets, A1AT and MIF, were evaluated, using selected reaction monitoring-mass spectrometry (SRM-MS), in whole saliva, collected prior to oncologic treatment. The results obtained from the targeted proteomic analysis were correlated with OM clinical outcomes.

RESULTS

A total of 27 patients were included, of whom 21 (77.8%) had locally advanced disease (clinical stage III or IV). Most patients (70.4%) received CRT. OM grades 2 (40.8%) and 3 (33.3%) were the most prevalent during RT with a mean highest reported OM-related pain of 3.22 through the visual analogue scale (VAS). The abundance of A1AT and MIF correlated significantly with severe (grades 3 or 4, p < 0.02) compared with moderate-low (grades 1 or 2, p < 0.04) OM grade.

CONCLUSIONS

There is a correlation between the abundance of salivary A1AT and MIF and oncologic treatment-induced OM. The correlation of MIF expression with severe OM appears to be compatible with its physiological pro-inflammatory role. These results open up great possibilities for the use of salivary MIF and A1AT levels as prognostic markers for effective therapeutic interventions, such as photobiomodulation therapy, patient-controlled analgesia, or personalized medicaments.

MASCC/ISOO clinical practice guidelines for the management of mucositis secondary to cancer therapy

BACKGROUND

Mucositis is a significant toxicity of cancer therapy with numerous systemic sequelae. The goal of this systematic review was to update the Multinational Association of Supportive Care in Cancer and International Society of Oral Oncology (MASCC/ISOO) Clinical Practice Guidelines for the management of mucositis.

METHODS

The literature was reviewed systematically to identify interventions for mucositis. Studies were rated according to the presence of major and minor flaws according to previously published criteria. The body of evidence for each intervention and in each treatment setting was assigned a level of evidence based on previously published criteria. Guidelines were developed based on the level of evidence, with 3 possible guideline determinations: recommendation, suggestion, or no guideline possible.

RESULTS

The guideline covers evidence from 1197 publications related to oral or gastrointestinal mucositis. Thirteen new guidelines were developed for or against the use of various interventions in specific treatment settings, and 11 previous guidelines were confirmed after aa review of new evidence. Thirteen previously established guidelines were carried over because there was no new evidence for these interventions.

CONCLUSIONS

The updated MASCC/ISOO Clinical Practice Guidelines for mucositis provide professional health caregivers with a clinical setting-specific, evidence-based tool to help with the management of mucositis in patients who have cancer.

Effects of photobiomodulation on cellular viability and cancer stem cell phenotype in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy; it has been shown that cancer stem cells (CSC) are present in OSCC and associated with tumor growth, invasion, metastasis, and therapeutic resistance. Photobiomodulation (PBM) is an alternative tool for oncologic treatment adverse effects such as oral mucositis (OM); however, controversy exists regarding the undesirable effects of PBM on tumor or CSC. This study aimed to evaluate in vitro, the effects of PBM, with the same dosimetric parameters as those used in the clinic for OM prevention and treatment, on OSCC cellular viability, as well as PBM's effect on CSC properties and its phenotype. OSCC cell lines were submitted to single or daily PBM with 3 J/cm² and 6 J/cm² and then the cellular viability was evaluated by MTT, NRU (neutral red uptake), and CVS (crystal violet staining). The CSC populations were evaluated by clonogenic formation assay, flow cytometry, and RT-qPCR. The single PBM with the 3 J/cm² group was associated with increased cellular viability. Daily PBM with 3 J/cm² and 6 J/cm² was associated with a significant decrease in cellular viability. Additionally, daily PBM was not able to promote CSC self-renewal or the CD44^high/ESA^low and CD44^high/ESA^high cellular phenotypes. Moreover, a decrease in the number of spheres and in the expression of the CSC related gene BMI1 was observed after daily PBM with 6 J/cm². Daily PBM with 3 J/cm² and 6 J/cm² showed an inhibitory effect on cellular viability and was not able to promote the CSC self-renewal or phenotype.

Photobiomodulation and Oral Mucositis: A Systematic Review

Oral mucositis (OM) is a debilitating complication of chemotherapy, and head and neck radiotherapy. In an effort to offer the best possible advice within the limitations of published research, a systematic review with an extended discussion and commentary on dosimetry and dose delivery is presented. Using keywords as listed, Pubmed, Google Scholar and Cochrane databases were searched during a period extending from 1995 to 2019. A total of 782 abstracts were identified. A total of 50 papers were analysed, and of these, 29 satisfied criteria required for systematic review in accordance with an optimized PRISMA statement. Clinical outcome as reported was subject to analysis with respect to time of intervention, incidence and severity of oral mucositis, and pain amelioration, and a comprehensive combined univariate and multivariate statistical analysis of the methods employed was performed. Recommendations are made with respect to the timing of the intervention. Moreover, there is an extended discussion available on the treatment care rationale of photobiomodulation (PBM), and its adjunctive association with OM. In conclusion, early prophylactic application offers clear advantages in clinical management. The many studies and associated variables and covariables assessed here revealed a choice of delivery techniques, associated wavelengths and many further indices to consider with regard to the accomplishment of optical parameters. It is therefore our recommendation that clinicians use PBM as a therapy with a full and proper understanding and training in order to optimise the clinical effects achievable.

Review on the Cellular Mechanisms of Low-Level Laser Therapy Use in Oncology

Photobiomodulation (PBM) using low-level laser therapy (LLLT) is a treatment that is increasingly used in oncology. Studies reported enhancement of wound healing with reduction in pain, tissue swelling and inflammatory conditions such as radiation dermatitis, oral mucositis, and lymphedema. However, factors such as wavelength, energy density and irradiation frequency influence the cellular mechanisms of LLLT. Moreover, the effects of LLLT vary according to cell types. Thus, controversy arose as a result of poor clinical response reported in some studies that may have used inadequately planned treatment protocols. Since LLLT may enhance tumor cell proliferation, these will also need to be considered before clinical use. This review aims to summarize the current knowledge of the cellular mechanisms of LLLT by considering its effects on cell proliferation, metabolism, angiogenesis, apoptosis and inflammation. With a better understanding of the cellular mechanisms, bridging findings from laboratory studies to clinical application can be improved.

Photobiomodulation Therapy in Oral Mucositis and Potentially Malignant Oral Lesions: A Therapy Towards the Future

Photobiomodulation therapy (PBMT) is an effective treatment modality, which has the significant advantage of enhancing a patient’s quality of life (QoL) by minimising the side effects of oral cancer treatments, as well as assisting in the management of potentially cancerous lesions. It is important to note that the major evidence-based documentation neither considers, nor tackles, the issues related to the impact of PBMT on tumour progression and on the downregulation of cellular proliferation improvement, by identifying the dose- and time-dependency. Moreover, little is known about the risk of this therapy and its safety when it is applied to the tumour, or the impact on the factor of QoL. The review aimed to address the benefits and limitations of PBMT in premalignant oral lesions, as well as the conflicting evidence concerning the relationship between tumour cell proliferation and the applied dose of photonic energy (fluence) in treating oral mucositis induced by head and neck cancer (H&N) treatments. The objective was to appraise the current concept of PBMT safety in the long-term, along with its latent impact on tumour reaction. This review highlighted the gap in the literature and broaden the knowledge of the current clinical evidence-based practice, and effectiveness, of PBMT in H&N oncology patients. As a result, the authors concluded that PBMT is a promising treatment modality. However, due to the heterogeneity of our data, it needs to undergo further testing in well-designed, long-term and randomised controlled trial studies, to evaluate it with diligent and impartial outcomes, and ensure laser irradiation’s safety at the tumour site.

Patterns of oral mucositis in advanced oral squamous cell carcinoma patients managed with prophylactic photobiomodulation therapy-insights for future protocol development

To characterize oral sites affected by radiation-induced oral mucositis (OM) and related clinical outcomes in oral cancer patients subjected to prophylactic photobiomodulation therapy (PBMT). This study included advanced oral squamous cell carcinoma (OSCC) patients treated with prophylactic PBMT for OM. The site distribution of OM, OM grading (CTCAE NCI, Version 4.0, 2010), OM-related pain (VAS), analgesic protocol (WHO Analgesic Ladder), and use of enteral nutrition were evaluated weekly during treatment. Data analysis was performed using descriptive statistics expressed as median values and percentages. A total of 145 OSCC patients were included. OM most frequently affected the lateral border of the tongue (44.1%), buccal mucosa (37.2%), and labial mucosa (33.8%). Keratinized oral mucosa sites, including the tongue dorsum (6.21%), retromolar trigone (8.3%), and hard palate (2.76%), were less frequently affected. Peak OM scores were observed at weeks 5, 6, and 7, with severe OM (NCI grades 3 and 4) rates of 11%, 20%, and 25%, respectively. The cumulative occurrence of severe OM was 23%, which developed as early as week 3 and as late as week 7. The highest mean value of OM-related pain (2.7) was observed at the sixth week, and 13.8% of the patients required feeding support. This study showed, compared with studies that did not provide PBMT, reduced severity of mucositis, reduced pain and analgesic use, and reduced tube feeding in patients treated with PBMT. OM involving keratinized and non-keratinized surfaces should be included in the prophylactic PBMT to reduce severe OM in future studies.

Does low-level laser therapy affect the survival of patients with head and neck cancer?

Low-level laser therapy (LLLT) is used in patients with head and neck cancer (HNC) for treatment-related mucositis. There is conflicting evidence as to whether LLLT leads to the proliferation of tumor cells and whether it interferes with the tumoricidal effect of radiotherapy or chemoradiotherapy, if the tumor lies within the LLLT field. Using fuzzy matching, 126 HNC patients who had received LLLT including the tumor region and 126 matching HNC patients without LLLT (controls) treated at the Department of Otorhinolaryngology, Head & Neck Surgery, Medical University of Innsbruck, were identified. The overall survival was compared using the Kaplan-Meier analysis. Fuzzy matching yielded 2 patient samples well comparable in terms of risk of death. The survival did not significantly differ between patients with and without LLLT (p = 0.18). An increased risk of death in HNC patients who received LLLT covering the tumor region was not observed in our study.

The impact of photobiomodulation therapy on the biology and behavior of head and neck squamous cell carcinomas cell lines

Photobiomodulation therapy (PBMT) is an emerging therapeutic modality designed to prevent and treat chemotherapy-driven oral mucositis (OM). However, the response of tumor cells to the effects of PBMT remains poorly understood. Our study explores the effects of PBMT in head and neck squamous cell carcinoma (HNSCC) based on cellular proliferation, migration, and survival of tumor cells and its population of cancer stem cells (CSC). We explored the behavior of two HNSCC cell lines (HN6 and HN13) under two distinct conditions, a physiological growing condition (10% FBS), and under stress growing condition (2% FBS) prior to irradiation using diode laser (InGaAlP; MM Optics, São Carlos, SP, Brazil). Diode laser (660 nm) was applied with a power of 100 mW delivering a total energy per point of 0.24 J. MTT and wound healing test (scratch assay) were performed to evaluate, respectively, proliferation and migration of tumor cells. Clonogenic and spheres formation assays were also performed to evaluate the survival and percentage of CSC upon irradiation. Overall, we observed that PBMT does not exacerbate the behavior of HNSCC. We could only observe a decrease in cellular proliferation of one cell line (HN6) when cultured under nutritional stress conditions (p < .05). There were no significant differences between the control and the PBMT groups regarding cell migration, survival and the percentage of CSC. Collectively, our results suggest that in vitro administration of PBMT to HNSCC does not modify the behavior of tumor cells.

Young head and neck cancer patients are at increased risk of developing oral mucositis and trismus

OBJECTIVES

To evaluate cancer treatment-related toxicities in young head and neck cancer (HNC) patients.

MATERIAL AND METHODS

A total of 44 patients were included in the present retrospective cohort study, which was designed to access oral toxicities of cancer treatment in young (< 45 years of age, Group I, n = 22) and old (> 58 years of age, Group II, n = 22) HNC patients with similar tumor stage and treatment protocols. Oral mucositis (OM), xerostomia, dysphagia, dysgeusia, trismus, and radiodermatitis were assessed during days 7th, 21st, and 35th of head and neck radiotherapy (HNRT) according to previously validated scales (World Health Organization criteria and the National Cancer Institute and Common Terminology Criteria for Adverse Events version 4.0).

RESULTS

Patients from both groups showed high incidence and severity of oral toxicities by the end of the HNRT with OM (81.9% (Group I); 63.6% (Group II)) and xerostomia (72.6% (Group I); 77.2% (Group II)) being the most prevalent toxicities. No differences regarding xerostomia, dysphagia, dysgeusia, and radiodermatitis incidences or severity could be observed between groups. However, higher incidences and severity of OM at 21st and 35th fractions (odds ratio = 2.22 and 5.71, respectively) and trismus at 21st and 35th fractions (odds ratio = 6.17 and 14.5, respectively) were observed throughout the treatment in young patients when compared to older patients (p < 0.01 and p < 0.05, respectively).

CONCLUSION

Young HNC patients are more affected by cancer treatment-related OM and trismus despite the similarities in clinical staging and treatment protocols with elderly patients.