Significant Response to Palbociclib Plus Lenvatinib as Second-line Treatment for CDKN2A/2B Deletion Intrahepatic Cholangiocarcinoma: A Case Report.

Cyclin-dependent kinase inhibitor 2A/2B (CDKN2A/2B) deletions are frequently identified in patients with biliary tract cancer; however, standard treatment options for this genetic alteration are lacking. Here, we present the case of a 64-year-old woman diagnosed with intrahepatic cholangiocarcinoma and hilar lymph node metastasis who underwent radical surgery. Postoperative pathology confirmed moderately differentiated adenocarcinoma. The tumor recurred during the second cycle of adjuvant chemotherapy following surgery, and the metastatic sites included the cranial region, right lung, and right adrenal gland. Genetic analysis revealed a CDKN2A/2B deletion, indicating palbociclib sensitivity. Subsequently, the patient received palbociclib plus lenvatinib as systemic therapy, along with stereotactic radiotherapy for the intracranial lesion. Notably, the right pulmonary metastasis significantly regressed after 12 months of treatment, with the complete disappearance of the intracranial tumor. However, the disease progressed at 32.2 months, with significant enlargement of the right adrenal gland metastasis and new metastasis in the right lung. The progression-free survival and overall survival were 32.2 months and 34.4 months, respectively. In conclusion, our case demonstrates that palbociclib plus lenvatinib is a promising chemotherapy-free second-line treatment for intrahepatic cholangiocarcinoma with a CDKN2A/2B deletion.