1468 - Topical silymarin administration for prevention of radiodermatitis in breast cancer patients: a randomized, double-blind, placebo-controlled clinical trial

Background

Breast cancer is the most common cancer among women. Radiation therapy is one of its main treatment modality. Radiation-induced dermatitis is one of the most common side effects that, in severe cases, may result in treatment discontinuation or delay. Silymarin is a polyphenolic flavonoid extracted from the Silybum marianum that exhibits strong antioxidant and anti-inflammatory activities. The purpose of this study was to investigate the topical silymarin formulation, in prevention of radiodermatitis in patients with breast cancer.

Methods

During this randomized, double-blinded, placebo-controlled clinical trial, the effect of silymarin 1% gel was assessed in comparison with placebo formulation, on radiodermatitis occurrence. In this study 40 patients with breast cancer who completed inclusion and exclusion criteria were randomly assigned to receive medicine or placebo formulation on breast twice daily starting at the first day of radiotherapy for 5 weeks. All patients were treated with radiation therapy at a dose of 50 Gy. Radiodermatits severity were assessed weekly based on Radiation therapy oncology group (RTOG) and national cancer institute common terminology for adverse event (CTCAE) criteria for 5 weeks.

Results

Significant difference was observed between the treatment and placebo groups, regarding the NIH CTCAE and RTOG scores at the end of the 4^th and 5^th weeks (Pvalue<0.05) but not at the end of the first three weeks. The median NIH CTCAE and RTOG scores were significantly lower in silymarin group at the end of the third to fifth weeks (Pvalue<0.05) . The scored increased significantly in both placebo and silymarin groups during radiotherapy, but there were a delay for radiodermatitis development and progression in silymarin group.

Conclusions

Prophylactic administration of silymarin topical formulation could significantly reduce the severity of radiodermatitis and delay its occurrence, in patients with breast cancer after 5 weeks of application.

Editorial acknowledgement

Clinical trial identification

IRCT2016110730760N1.

Legal entity responsible for the study

Mashhad University of Medical Sciences.

Funding

Mashhad University of Medical Sciences.

Disclosure

All authors have declared no conflicts of interest.