Camrelizumab in combination with chemotherapy versus concurrent chemoradiotherapy for the conversion of locally advanced unresectable oesophageal squamous carcinoma: protocol for a two-arm, open-label phase II trial.

INTRODUCTION: Oesophageal cancer (OC) has higher morbidity and mortality rate than most other malignancies. The standard treatment for unresectable locally advanced oesophageal squamous cell carcinoma (OSCC) is concurrent chemoradiotherapy, with tumour regression observed in a proportion of patients after treatment, but prognostic improvement remains limited. Immunotherapy in combination with chemotherapy (CT) has been shown to be efficacious as the first-line treatment of advanced OC and neoadjuvant therapy. Therefore, we conducted a prospective, two-arm, randomised, unblinded phase II study to explore the efficacy of camrelizumab in combination with CT versus chemoradiotherapy for the conversion of unresectable advanced OSCC.

METHODS AND ANALYSIS: All participants meeting the inclusion criteria will be enrolled after signing an informed consent form. Patients with clinically cT4b or spread to at least one group of lymph nodes with possible invasion of surrounding organs and unresectable locally advanced squamous carcinoma of the thoracic segment of the oesophagus will be included in the study. Patients with suspected distant metastases on the preoperative examination will be excluded from this study. Patients eligible for enrolment will be grouped by centre randomisation according to the study plan. Patients will undergo radical surgery after completion of two cycles of chemotherapy (CT) combined with camrelizumab induction therapy or concurrent chemoradiotherapy if assessed to be operable. Patients evaluated as inoperable will be scheduled for a multidisciplinary consultation to determine the next treatment option. The primary endpoint is the R0 resection rate in patients undergoing surgery after treatment. Secondary endpoints are the rate of major pathological remission, pathological complete response rate, overall survival, progression-free survival and adverse events for all patients.

ETHICS AND DISSEMINATION: Ethical approval was obtained from the ethics committees of Fujian Medical University Union Hospital (No. 2022YF039-02). The findings will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER: NCT05821452.