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.

Differential responses of fibroblasts, non-neoplastic epithelial cells, and oral carcinoma cells to low-level laser therapy.

Low-level laser therapy (LLLT) is used in the treatment of chemoradiotherapy- or radiotherapy-induced oropharyngeal mucositis (ORM). In head and neck cancer, tumor cells may lie in the LLLT irradiation field, and LLLT might promote tumor progression. We therefore investigated the effect of LLLT on proliferation, cell cycle distribution, and apoptosis in a human oral carcinoma cell line (SCC-25), non-malignant epithelial cells (BEAS-2B), and fibroblasts in vitro. The cell lines were subjected to LLLT on three consecutive days for 15 min. Cell proliferation was assessed using the MTT assay, cell cycle distribution by flow cytometry and propidium-iodide DNA staining, and apoptosis using an Annexin V-FITC assay. Controls were sham-treated, but not exposed to the laser treatment. LLLT treatment resulted in increased fibroblast proliferation (p < 0.001), whereas decreased cell proliferation was observed after LLLT treatment of BEAS-2B (p = 0.003) and SCC-25 cells (p < 0.001). In SCC-25 cells, an increased percentage of S-phase cells and decreased percentage of G1-phase cells were observed (p < 0.001). Moreover, a proapoptotic effect of LLLT was observed in SCC-25 cells (p = 0.02). LLLT did not exhibit a tumor-promoting effect in this in vitro study.