Preventive Effect of Boron-based Gel on Radiation Dermatitis in Patients With Breast Cancer: Phase III Randomized, Double-blind, Placebo-controlled Clinical Trial

• Study aim: Radiation dermatitis (RD) is observed in more than 90% of breast cancer patients who receive the radiation therapy (RT). In spite of the high number of studies in this area, there is limited high-quality and comparative research that presents definitive findings suggesting the effectiveness of any single intervention for RD prevention. So, the current phase III clinical trial study was conducted to measure the preventive effects of the aforementioned boron-based gel on different outcomes.
• Design: The parallel design, randomized, double blinded and placebo controlled phase III clinical trial was conducted. One-hundred-eighty-one and seventy-six patients aged 18-75 years were assigned to intervention and placebo groups respectively. Patients in intervention and placebo groups received daily a gel containing 3% sodium pentaborate pentahydrate and gel free of any chemical treatment respectively 15 minutes before the RT session. Dermatitis, erythema, dry desquamation, moist desquamation and necrosis were compared between two groups in terms of percent and number needed to treat.
• Settings and conduct: The female breast cancer patients who admitted to the Shahid Madani Hospital were initially assessed during 2018-2019 and those aged 18-75 years old with no previous history of radiotherapy were invited to the study. Pregnant women, patients with unknown dermatitis and those without any willing to participate in this study were excluded. As there was no similar study to compare our outcome studied, we included 30 patients in the pilot study. Afterwards, the sample size of 16 were calculated for each group based on the erythema to ensure the power of 0.8 and type I error of 0.05. However, we increased the sample size of the study to 181 and 76 subjects in intervention and placebo groups respectively to meet the sample size guidelines for Food and Drug Administration Phase III Clinical Trial Studies, address at least 20% attrition rate during the study, and to enhance the randomization efficiency in balancing the patterns of confounding variables between intervention and placebo groups. As there was no usual treatment for the radiation dermatitis in breast cancer patients, increasing the sample size was not ethically questionable.
• Participants/Inclusion and exclusion criteria:

Inclusion: Patients who are admitted to the study are enrolled in the study and have head and neck cancer in the breast, and are between the ages of 18 and 75 years old and have not received radiotherapy before.

Exclusion: Pregnant women, patients with unknown dermatitis and those without any willing to participate in this study were excluded.

• Intervention groups: The aim of the study was fully described to the eligible subjects and informed consent was gathered. Afterwards, the patients were assigned into the intervention and placebo groups. In the intervention and placebo groups, subjects received daily a gel containing 3% sodium pentaborate pentahydrate and gel free of any chemical treatment respectively 15 minutes before the radiotherapy session. As the gels were used on the target areas of the patients by the researchers, there was no compliance problem in this study. Afterwards, the study's outcomes were examined at 25th day of treatment for the patients in two groups.
• Main outcome variables: Dermatitis and its grades including erythema, dry desquamation, moist desquamation and necrosis were considered as main outcomes in this study based on the Radiation Therapy Oncology Group (RTOG) criteria.