Case Report
A 53-year-old woman presented to the hospital with a chief complaint of abdominal pain. Contrast-enhanced computed tomography (CT) revealed a large tumor on the right lobe of the liver, multiple lung tumors, multiple enlarged lymph nodes, and peritoneal dissemination. A liver tumor biopsy was performed, which confirmed ICC. Therefore, the patient was diagnosed with unresectable ICC (cT4N1M1, cStage IVB). The patient had a history of gastric ulcers but without a family history of cancer, medication maintenance, and allergies. Due to extensive metastasis and declining performance status, the patient was treated with S-1 (100 mg/day) as the first-line treatment. Progressive disease (PD) due to increased pulmonary metastasis and peritoneal dissemination by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 was observed after 5 months of S-1 treatment, and gemcitabine of 500–800 mg/m2/day + cisplatin of 13–20 mg/m2/day (GC) therapy was started as the second-line treatment. GC therapy was administered for 11 months; however, PD due to increased bone metastasis and peritoneal dissemination occurred. Therefore, CGP was performed to identify treatment options. The specimen from the initial liver tumor biopsy performed to diagnose ICC was insufficient for CGP submission. Thus, liver tumor biopsy and CT-guided lymph node biopsy were performed to inspect CGP; however, a viable specimen could not be obtained. Therefore, liquid CGP (FoundationOne® Liquid CDx, Foundation Medicine, Cambridge, USA) was performed, and FGFR2 fusion was detected. The results revealed that this patient could use pemigatinib (13.5 mg/day) as the third-line treatment. Two months after initiating pemigatinib, a CT scan showed controlled intrahepatic lesions and other distant metastases, and the state of the cancer was considered a stable disease based on RECIST (version 1.1) (Figure 1). However, specific side effects (nail disorders, hyperphosphatemia, and taste disorders) should be addressed after initiating pemigatinib. Because nail disorders were classified as grade 3 (Criteria for adverse events version 4.0 [CTCAE ver.4.0]), pemigatinib was reduced to 9.0 mg/day 3 months after initiating pemigatinib (Figure 2). Nail disorders were managed by reducing the pemigatinib dosage, administering topical steroids and moisturizers, and taping in collaboration with the dermatologist. Hyperphosphatemia was treated with a phosphorus-restricted diet and lanthanum carbonate. Nutritionists were asked to address taste disorders and recommended that the patient should eat foods that could be tasted easily and gargled with warm water. Due to nail disorders and taste disorders, the pemigatinib dosage was reduced to 4.5 mg/day 2 months after reducing it to 9.0 mg/day. Despite her recurrent cholangitis and strong pemigatinib side effects, she managed to continue pemigatinib with repeated medication withdrawal as needed; however, she died 26 months after being diagnosed with stage IVB ICC. The treatment progression is shown in Figure 3.