Adjusted gemcitabine plus S-1 regimen as first‑line chemotherapy in unresectable advanced pancreatic cancer: a long-term survival case report.

Background: The gemcitabine plus S-1 (GS) regimen is a first-line chemotherapy for unresectable locally advanced or metastatic pancreatic cancer (PC), a disease associated with high mortality. However, severe adverse events associated with the standard GS (gemcitabine plus daily S-1) regimen adversely affect treatment adherence and clinical outcomes. Recent studies suggest that modified GS regimens may improve tolerability without compromising efficacy in select populations. Here, we report a case demonstrating that an adjusted GS (gemcitabine plus alternate-day S-1) regimen could represent a viable alternative first-line chemotherapy for patients with standard GS protocol intolerance. Case Description: In January 2020, a 61-year-old female with upper abdominal pain was diagnosed with unresectable locally advanced pancreatic ductal adenocarcinoma (PDAC) confirmed by biopsy (T3N0M1). She received one cycle of standard GS chemotherapy but developed severe toxicity (grade 3 neutropenia and stomatitis). Given the intolerance, the patient was transferred into an adjusted GS regimen (gemcitabine 1,000 mg/m Conclusions: This case highlights the potential of an adjusted GS regimen to achieve prolonged disease control and manageable toxicity in patients with standard GS intolerance. This modified approach may serve as a potential alternative to the standard GS regimen for select patients who experience intolerance to conventional therapy. A future multicenter randomized controlled study will investigate the efficacy and safety of this adjusted GS treatment strategy.