Abscopal Resolution of a Hepatic Metastasis in a Patient with Metastatic Cholangiocarcinoma Following Radical Stereotactic Body Radiotherapy to a Synchronous Early Stage Non-small Cell Lung Cancer

This case report describes the abscopal resolution of a liver metastasis in a patient with two separate primary malignancies. A 70-year-old male with an unresectable cholangiocarcinoma with an associated 5 cm liver metastasis was found during his staging investigations to have a 1.8 cm right upper lobe lung tumor. A CT-guided biopsy of the lung tumor revealed a primary adenocarcinoma of lung origin. Given the expected worse prognosis of the metastatic cholangiocarcinoma, after review of his case in provincial gastrointestinal and lung tumor boards, he was treated with eight cycles of palliative gemcitabine and cisplatin chemotherapy. Post eight cycles, the disease in the liver and the lung was stable. After completion of first line palliative systemic therapy, radical stereotactic body radiotherapy (SBRT), consisting of 48 Gy in four fractions, was delivered to the right upper lobe non-small cell lung cancer (NSCLC) primary. Three months post-completion of the SBRT, restaging CT scans were performed which revealed the intriguing spontaneous and complete resolution of his liver metastasis. These findings were confirmed on subsequent MRI imaging of his liver. As his liver metastasis was well outside of the SBRT fields, the spontaneous resolution of his liver metastasis presents clinical evidence of the abscopal effect of cholangiocarcinoma in response to SBRT to his lung tumor.