Tumor disappearance on positron emission tomography computed tomography after S-1 treatment for postoperative local recurrence of gallbladder cancer

Objective: Gallbladder cancer (GBC) typically follows an aggressive course with the standard of care for advanced disease; complete responses are rarely encountered. We report a case in which tumor disappearance on positron emission tomography computed tomography (PET-CT) was treated with S-1 as the second-line treatment for local recurrence of GBC after gemcitabine (GEM) plus cisplatin (CDDP) (GC) combination therapy. Case Presentation: A 69-year-old woman was referred to our hospital with complaints of right hypochondrial pain. Based on ultrasound, CT, and magnetic resonance imaging (MRI) findings, we diagnosed patient with suspected GBC. Results: We performed the resection of the gallbladder base, partial resection of the transverse colon, and partial resection of the stomach for GBC. At four months after the surgery, PET-CT showed local recurrence. First-line chemotherapy with GC therapy was initiated. After 9 courses, PET-CT showed increased local recurrence. We concluded that GC treatment was ineffective. Second-line chemotherapy with S-1 was initiated for two weeks, followed by a 7-day rest period. PET-CT in September 2019 showed the markedly reduction of the local recurrence, and PET-CT in October 2021 showed the complete disappearance of the local recurrence. At 20 months after the discontinuation of S-1, PET-CT showed the complete disappearance of the local recurrence. Conclusions: Chemotherapy with S-1 can be managed safely and was demonstrated to be effective in treating the local recurrence of GBC recurrence.