Ursodeoxycholic acid for the prevention of severe radiation dermatitis: a single-arm phase I/II trial protocol in patients with breast cancer undergoing postoperative radiotherapy in China.

BACKGROUND

Breast cancer poses a significant threat to public health, as demonstrated by its high incidence rate. While postoperative radiotherapy remains an important adjuvant treatment for patients with breast cancer undergoing breast-conserving surgery, radiation-induced dermatitis (RID) is a prevalent side effect, for which no standardised prevention method currently exists. Our previous preclinical research demonstrated that ursodeoxycholic acid (UDCA) significantly reduced radiation-induced skin damage in mice. Therefore, this phase I/II clinical study aims to further evaluate the safety and efficacy of UDCA in preventing RID during adjuvant radiotherapy in patients with breast cancer after breast-conserving surgery.

METHODS AND ANALYSIS: This single-centre phase I/II clinical study, with a single-arm cohort design in phase II, will include female patients who have undergone adjuvant radiotherapy after breast-conserving surgery for breast cancer. The sample size for the study is 40. Eligible patients will receive adjuvant radiotherapy at a prescribed dose of 50 Gy/25 F to the entire breast and lymphatic drainage area, where indicated, and 66 Gy/33 F to the tumour bed. After each irradiation, a 250 mg dose of UDCA will be topically administered to the irradiated area. Radiological dermatitis and skin temperature were assessed once a week after the initiation of radiotherapy, and haematological toxicity, radiation lung injury and quality of life were monitored and analysed on a regular basis until the second week after the conclusion of radiotherapy. The primary objectives of phase I and II studies are the safety profile and incidence of grade II or higher RID in patients, respectively.

ETHICS AND DISSEMINATION: This study was approved by the ethics committee of Mianyang Central Hospital, China (No: S20230211-02) and is registered in the Chinese Clinical Trial Register (registration number: ChiCTR2400085925). Results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER: ChiCTR2400085925.