SOME: sintilimab plus chemotherapy followed by definitive local therapy for oligometastatic thoracic esophageal squamous cell carcinoma-a multicenter, prospective, open-label phase II trial.

First-line therapy for recurrent or metastatic esophageal squamous cell carcinoma (ESCC) currently consists of a programmed cell death protein 1 inhibitor plus platinum-based chemotherapy. Previous studies have indicated selected patients with synchronous oligometastatic ESCC may benefit from intensified curative-intent local therapy; however, prospective trials dedicated to treating patients with this specific disease are lacking. The SOME trial will prospectively explore whether patients with synchronous oligometastatic thoracic ESCC who undergo protocol-defined curative-intent local treatment after systemic therapy may have more favorable overall survival than patients with polymetastatic disease treated with systemic therapy alone. In this phase II trial, systemic anticancer therapy-naive thoracic ESCC patients will be enrolled and assigned by stage and metastatic burden to cohort A (locally advanced resectable), cohort B (synchronous oligometastatic ESCC), or cohort C (polymetastatic ESCC not meeting oligometastatic disease criteria). A total of 148 patients will be enrolled (37 in cohort A, 37 in cohort B, and 74 in cohort C). All patients will receive sintilimab plus platinum-based chemotherapy, and cohorts A and B will additionally receive curative-intent local therapy. The primary endpoint is overall survival. The secondary endpoints are progression-free survival and disease-free survival, among others.Clinical trial registration: Chinese Clinical Trial Registry (http://www.chictr.org.cn), identifier is ChiCTR2500108825.