Durable response to chemotherapy enabling conversion surgery in stage IVB gallbladder cancer: a case successfully treated with durvalumab combined with gemcitabine plus cisplatin.

Gallbladder cancer with distant lymph node metastases is typically considered unresectable and carries a poor prognosis. We present a rare case of Stage IVB gallbladder cancer with bulky hilar and para-aortic lymph node metastases successfully treated with systemic chemotherapy followed by conversion surgery. The patient received prolonged gemcitabine-cisplatin therapy, during which significant regression of nodal metastases was observed. With the subsequent addition of durvalumab, a sustained nodal response was confirmed. Twenty-four months after treatment initiation, the patient underwent extended cholecystectomy with para-aortic and hilar lymphadenectomy. R0 resection was achieved, with only one metastatic lymph node identified at resection. Histologically, the primary tumor exhibited limited response (Evans grade I), whereas the nodal disease responded markedly. At the time of writing, the patient remains recurrence-free 12 months postoperatively. This case highlights the potential role of systemic chemotherapy-including immune checkpoint inhibition-in enabling curative-intent conversion surgery in selected patients with advanced gallbladder cancer. Careful patient selection, durable disease control, and multidisciplinary assessment may be essential to achieving favorable outcomes in such challenging cases.