Efficacy of topical Calendula officinalis on prevalence of radiation-induced dermatitis: A randomised controlled trial

Objectives: A randomised controlled trial was undertaken to compare the efficacy of topical Calendula officinalis (Calendula) versus standard of care (Sorbolene: 10% glycerine in cetomacragol cream) in reducing the prevalence of radiation-induced dermatitis in women undergoing breast cancer radiotherapy.

Methods: A total of 271 women were screened and 82 were randomised. The primary outcome was prevalence of acute radiation-induced dermatitis (RTOG grade 2+) assessed at multiple skin sites. A chi-squared test was conducted for the primary outcome with a worst-case scenario imputation.

Results: The recruitment target (n = 178) was not achieved. A total of n = 81 participants were analysed (n = 40 Calendula; n = 41 Sorbolene). There was no detectable difference in prevalence of radiation-induced dermatitis grade 2+ between the Calendula (53%) and Sorbolene (62%) groups (primary analysis OR = 0.87, 95% CI: [0.36, 2.09], P = 0.92; covariate adjusted complete case analysis OR 0.40, 95% CI: [0.13, 1.20], P = 0.10).

Conclusion: This randomised controlled trial showed no difference between Calendula and standard of care (Sorbolene) for the prevention of radiation-induced dermatitis. However, the study was underpowered (limited recruitment) for the primary comparison.

Keywords: adjuvant; calendula; ointments/therapeutic; radiodermatitis; radiotherapy; randomised controlled trial.