Impact of Long-Term Chemotherapy on Outcomes in Pancreatic Ductal Adenocarcinoma: A Real-World UK Multi-Centre Study

Background: We reviewed outcomes of short and long-term chemotherapy with or without breaks in pancreatic ductal adenocarcinoma (PDAC) patients. Methods: PDAC patients receiving >= 3 chemotherapy cycles between 2019 and 2024 at three institutions were included. Progression-free survival after first-line chemotherapy (PFS1), overall survival (OS) and best overall response (BOR) to chemotherapy were assessed using the Wilcoxon test, Kaplan-Meier test, and univariate and multivariate Cox regression models. Results: We screened 237 patients, and 135 patients met the study criteria. Among these patients, 25 had resectable disease, and 110 had unresectable/metastatic disease (13% borderline resectable (BRPC), 20% locally advanced (LAPC), 10% localised developing metastases, 57% de novo metastatic). Ten patients (7%) underwent genetic profiling; KRAS aberrations (N = 4), actionable PLAB2/BRCA2/FGFR2 mutations (N = 3), ATM/BRIP1 alteration (N = 1). Two patients were managed with PARP inhibitors after receiving multiple lines of chemotherapy. Median PFS1 and OS were concordant with the published literature, but select patient groups achieved prolonged survival outcomes. Among the 36 BRPC/LAPC patients, we observed >1-year PFS1 in 9 (25%) patients and >2-year OS in 3 (8%) patients. Among the 63 de novo metastatic patients, we observed >1-year PFS1 and >2-year OS in 6 (10%) patients. Among patients with localised disease, smoking history was a poor prognostic factor with respect to OS (p = 0.03). Improved PFS1 and OS was associated with >= 6 cycles of first-line chemotherapy, its duration of >= 3.66 months, and local treatment after first chemotherapy (p < 0.05 for all). Stereotactic body radiotherapy following first-line chemotherapy was delivered in N = 6 (27%) and N = 1 (7%) of patients with LAPC and BRPC, respectively. Chemotherapy interruption duration, but not number, was associated with PFS1 and OS only in the localised cohort (p < 0.05). In patients with de novo metastatic disease, prevalence of type 2 diabetes was adversely associated with OS (p = 0.03). Improved PFS and OS was associated with >= 6 cycles of first-line chemotherapy, its duration of >= 4.37 months, and BOR to it (only in this cohort) (p < 0.05 for all). A favourable OS was associated with >1 line of chemotherapy (p = 0.003). Conclusion: Despite challenges, extended chemotherapy and multiple treatment lines may improve survival, with localised treatments benefiting select patients.