Effect of Oral Silymarin Administration on Prevention of Radiotherapy Induced Mucositis: A Randomized, Double-Blinded, Placebo-Controlled Clinical Trial.

Mucositis is a frequent severe complication of radiation therapy in patient with head and neck cancer. Silymarin is a polyphenolic flavonoid extracted from the milk thistle that exhibits strong antioxidant and antiinflammatory activities. In this study, we evaluate silymarin efficacy in prevention of radiotherapy induced mucositis in patients with head and neck cancer, as the first human study. During this pilot, randomized, double-blinded, placebo-controlled clinical trial, the effect of oral silymarin 420 mg daily in three divided doses starting at the first day of radiotherapy for 6 weeks, on oral mucositis occurrence was assessed. Twenty-seven patients fulfilled the inclusion criteria assigned to the silymarin or placebo group. World Health Organization and National Cancer Institute-Common Terminology Criteria oral mucositis grading scale scores were recorded at baseline and weekly during these 6 weeks. The median World Health Organization and National Cancer Institute Common Terminology Criteria scores were significantly lower in silymarin group at the end of the first to sixth week (p < 0.05). The scores increased significantly in both placebo and silymarin groups during radiotherapy, but there was a delay for mucositis development and progression in silymarin group. Prophylactic administration of conventional form of silymarin tablets could significantly reduce the severity of radiotherapy induced mucositis and delay its occurrence in patients with head and neck cancer.