Background The modulation of perioperative inflammation seems crucial to improve postoperative morbidity and cancer-related outcomes in patients undergoing oncological surgery. Data from the literature suggest that perioperative corticosteroids decrease inflammatory markers and might be associated with fewer complications in esophageal, liver, pancreatic and colorectal surgery. Their benefit on cancer-related outcomes has not been assessed. Methods The CORTIFRENCH trial is a phase III multicenter randomized double-blind placebo-controlled trial to assess the impact of a flash dose of preoperative corticosteroids versus placebo on postoperative morbidity and cancer-related outcomes after elective curative-intent surgery for digestive cancer. The primary endpoint is the frequency of patients with postoperative major complications occurring within 30 days after surgery (defined as all complications with Clavien-Dindo grade > 2). The secondary endpoints are the overall survival at 3 years, the disease-free survival at 3 years, the frequency of patients with intraabdominal infections and postoperative infections within 30 days after surgery and the hospital length of stay. We hypothesize a reduced risk of major complications and a better disease-survival at 3 years in the experimental group. Allowing for 5% of drop-out, 1 200 patients (600 per arm) should be included. Discussion This will be the first trial focusing on the impact of perioperative corticosteroids on cancer related outcomes. If significant, it might be a strong improvement on oncological outcomes for patients undergoing surgery for digestive cancers. Trial registration ClinicalTrials.gov, NCT03875690, Registered on March 15, 2019, URL: Keywords: Perioperative corticosteroids, Digestive surgical oncology, Randomized placebo-controlled trial, Postoperative morbidity, cancer-related outcomes