This single-center, open-label, randomized clinical trial evaluates the effect of 0.15% benzydamine hydrochloride (Difflam) oral spray on the severity of radiation-induced oral mucositis in patients with head and neck cancer receiving high-dose radiotherapy (≥50 Gy) without concurrent chemotherapy. Oral mucositis is a common and clinically significant complication of radiotherapy that can cause pain, difficulty swallowing, nutritional impairment, and treatment interruption.

Participants are randomly assigned to receive either standard oral care alone or standard oral care plus benzydamine oral spray for 6 weeks. Oral mucositis severity is assessed weekly using the World Health Organization (WHO) oral mucositis grading scale. The study aims to determine whether benzydamine reduces the progression and severity of oral mucositis in this patient population.

Inclusion Criteria:

• Age 22 years or older
• Pathologically confirmed head and neck cancer
• Currently undergoing RT
• Cumulative total radiation dose exceeding 50 Gy
• Patients were enrolled in the study after their diagnosis of OM was confirmed by a specialist, which occurred approximately two weeks after the initiation of radiotherapy
• All subjects had grade 1 OM according to the WHO criteria at baseline, except for two patients in the intervention group who presented with grade 2 severity at the start of the study
• None of participants received concurrent chemotherapy during the study period

Exclusion Criteria:

• Use of concurrent treatments affecting OM
• Incomplete follow-up
• Other conditions influencing its progression
• patient withdrawal