Validation and application of a prognostic model for patients with advanced pancreatic cancer receiving palliative chemotherapy

Background: We previously developed a robust prognostic model (GS model) to predict the survival outcome of patients with advanced pancreatic cancer (APC) receiving palliative chemotherapy with gemcitabine plus S-1 (GS). This study aimed to validate the application of the GS model in APC patients receiving chemotherapy other than the GS regimen. Patients and methods: We retrospectively analyzed 727 APC patients who received first-line palliative chemotherapy other than the GS regimen between 2010 and 2016 at four institutions in Taiwan. The patients were categorized into three prognostic groups based on the GS model for comparisons of survival outcome, best tumor response, and in-group survival differences with monotherapy or combination therapy. Results: The median survival times for the good, intermediate, and poor prognostic groups were 13.4, 8.4, and 4.6 months, respectively. The hazard ratios for the comparisons of intermediate and poor to good prognostic groups were 1.51 (95% confidence interval [CI]), 1.22-1.88, P <.001) and 2.84 (95% CI, 2.34-3.45, P <.001). The best tumor responses with either partial response or stable disease were 57.5%, 40.4%, and 17.2% of patients in the good, intermediate, and poor prognostic groups (P <.001), respectively. For patients in the good prognostic group, first-line chemotherapy with monotherapy and combination therapy had similar median survival times (13.8 vs 12.9 months, P =.26), while combination therapy showed a better median survival time than monotherapy in patients in the intermediate and poor prognostic groups (8.5 vs 8.0 months, P =.038 and 5.7 vs 3.7 months, P =.001, respectively). Conclusion: The results of our study supported the application of the GS model as a general prognostic tool for patients with pancreatic cancer receiving first-line palliative chemotherapy with gemcitabine-based regimens.