Durable complete response to sintilimab plus chemotherapy in gallbladder cancer with extensive metastasis: A case report

BACKGROUND Gallbladder cancer is a highly malignant and aggressive tumor, often diagnosed at an advanced stage. The prognosis for advanced gallbladder cancer remains poor, with limited options for effective treatment. CASE SUMMARY A 65-year-old male patient presented with a soft tissue mass in the gallbladder. Following laparoscopic exploration, he underwent radical surgery for gallbladder cancer, with the tumor staged as pT2N1M0 (stage III). Post-surgery, the patient received four cycles of adjuvant chemotherapy. However, one month later, over 60 metastatic lesions were detected in the liver, lungs, and lymph nodes. In response to the widespread metastasis, he underwent six cycles of combination therapy consisting of sintilimab, albumin-bound paclitaxel, and cisplatin. After two cycles, a partial response was achieved. Maintenance therapy was initiated with a combination of sintilimab and albumin-bound paclitaxel for four cycles. Monotherapy with sintilimab was continued thereafter until October 2023. Complete remission was confirmed in September 2021. The patient sustained this complete response for more than three years, including an eleven-month period without disease progression following the discontinuation of sintilimab. Genetic analysis revealed a tumor mutational burden of 15.4 mutations/megabase, which indicates a potentially favorable response to immunotherapy. CONCLUSION This case demonstrates the potential of combining immunotherapy (sintilimab) with chemotherapy to achieve durable remission in metastatic gallbladder cancer, even in a patient with extensive metastasis. In addition, it indicated the importance of tumor mutational burden as a predictive biomarker of immunotherapy.