Case Report: Successful R0 resection following conversion immunochemotherapy in a patient with biliary tract cancer and multiple metastases discovered after laparoscopic gallstone surgery.

Gallbladder cancer is usually discovered as an incidental finding during or after cholecystectomy for gallstones. Most patients have advanced gallbladder cancer at diagnosis and have lost the opportunity for radical surgery, leading to dismal prognosis. Standard conversion therapy regimen is still in exploration. We reported a patient with unresectable biliary tract cancer (most likely gallbladder cancer) and multiple metastases (TxN2M1) discovered one month after laparoscopic gallstone surgery. The patient received margin-free resection after 9 cycles of immunotherapy (camrelizumab) combined with chemotherapy, followed by adjuvant immunochemotherapy. Pathological complete response was achieved and no disease recurrence occurred 5 months after surgery. Decreased neutrophil count was the only grade 3-4 treatment-related adverse event during the 9 cycles of conversion therapy. This case provides some reference for the conversion therapy of advanced gallbladder cancer or other biliary tract cancers.