Gastrointestinal perforation during regorafenib administration in a case with hepatic metastases of colon cancer.

Although common side effects of regorafenib include hand-and-foot syndrome and diarrhoea, the incidence of gastrointestinal perforation is reportedly unknown. We describe our experience with the case of a 65-year-old woman treated with regorafenib as a third-line therapy for progressive caecal cancer with multiple hepatic metastases after 4 and 6 courses of systemic mFOLFOX6 + bevacizumab (BV) and FOLFIRI + BV chemotherapy, respectively. The patient used regorafenib for 32 days but visited our hospital with abdominal pain during the second course. She was diagnosed with acute appendicitis and treated conservatively with antibiotics. The abdominal findings did not improve, and a computed tomography evaluation on day 4 of hospitalization revealed free air lateral to the caecal tumour, liver surface, and epigastric region. The patient underwent same-day emergency surgery based on a diagnosis of gastrointestinal perforation with generalized peritonitis. Upon observing digestive fluid leakage into the peri-ileocaecal area and a 5-mm perforation in the appendix, the patient was diagnosed with peritonitis due to gastrointestinal perforation. Ileocaecal resection with D2 debridement was performed, and a colostomy was opened into the ileum and ascending colon. We conclude that our patient developed gastrointestinal perforation during regorafenib therapy and note that clinicians should be aware of this possible complication in patients with a history of prior treatment with BV.