Photobiomodulation for radiotherapy-induced dysgeusia in head and neck cancer patients: a pilot randomized clinical trial

Dysgeusia is a frequent complication in patients with head and neck cancer (HNC) undergoing radiotherapy and may negatively affect nutritional status and quality of life. This pilot study evaluated the effect of photobiomodulation (PBM) on the management of radiotherapy-induced dysgeusia. Sixteen patients undergoing radiotherapy for HNC were randomly assigned to either a PBM group (n = 8) or a zinc sulfate group (n = 8). Objective taste identification tests evaluating sweet, bitter, sour, and salty tastes were performed at three time points: before radiotherapy (T0), at the 15th radiotherapy session (T1), and at the 30th radiotherapy session (T2). Salty taste was the most affected taste modality in both groups. At T2, sweet taste was correctly identified by 75.0% of patients in the zinc group and 50.0% in the PBM group. In contrast, bitter taste was preserved in 87.5% of patients in the PBM group and 75.0% in the zinc group. Sour taste was preserved in 87.5% and 62.5% of patients in the PBM and zinc groups, respectively, whereas salty taste was preserved in 50.0% and 25.0% of patients, respectively. No statistically significant differences were observed between groups at T0, T1, or T2 (all p > 0.05). Although no statistically significant differences were identified, PBM was associated with better preservation of sour, bitter, and salty taste perception, particularly after the 30th radiotherapy session. These preliminary findings suggest that PBM may represent a promising supportive strategy for the management of treatment-related dysgeusia in patients with HNC undergoing radiotherapy.