A Case of Stereotactic Body Radiotherapy for Inoperable Intraductal Papillary Neoplasm of the Bile Duct

Intraductal papillary neoplasms of the bile duct (IPNBs) have a high propensity for malignant transformation; therefore, surgical resection remains the standard first-line treatment. In cases where hepatic lobectomy is not feasible, however, controlling biliary drainage can be challenging. We present herein a case of unresectable IPNB complicated by jaundice and cholangitis due to mucin production by the tumor. Stereotactic body radiation therapy (SBRT) has been used as a treatment modality, resulting in favorable outcomes. An 80-year-old male patient presented to the emergency room with symptoms of cholangitis, for which he had previously undergone endoscopic lithotripsy for the removal of choledochal stones. The persistent symptoms and viscous bile led to suspicions of IPNB; therefore, the patient underwent a peroral cholangioscopy with biopsy to confirm the diagnosis. Due to his compromised cardiac function, however, surgical resection was not deemed a viable option, and biliary drainage was attempted instead. Unfortunately, frequent mucin-induced obstructions of the catheter made it difficult to control the cholangitis; therefore, SBRT was administered to achieve local tumor control and reduce mucin production. The radiation was delivered using a 10 MV beam with a volumetric-modulated arc therapy, fiducial gold markers, and suspended exhalation. A total dose of 60 Gy was administered across eight fractions (planning target volume D95), and one month post-SBRT, the biliary dilation and cholangitis had resolved. No local tumor regrowth or recurrent cholangitis occurred for at least one year after treatment, nor were any significant adverse effects related to the SBRT observed. According to the Surveillance, Epidemiology, and End Results (SEER) database, SBRT has been performed for IPNB; however, only a few case reports have been identified, all of which were cases in which brachytherapy was performed. To our knowledge, this is the first case report detailing a treatment regimen of SBRT with a definite radiation dose. This case suggests that SBRT may be of value as an alternative therapy for cases in which surgical resection is not an option.