Metabolomic and Immune-Microbiome Profiling for Unresectable Pancreatic Cancer

Inclusion Criteria:

1. Unresectable disease status determined by a multidisciplinary tumour board (either locally advanced disease encasing critical vessels or distant metastases present).
2. Planned initiation of systemic therapy (first-line chemotherapy or chemo + experimental immunotherapy trial) as part of standard care - this ensures a uniform starting point for outcome measurement.
3. Adequate organ function to undergo therapy (renal, hepatic, bone marrow parameters within acceptable range) and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, indicating patients well enough to participate and undergo required blood draws and sample collection.
4. Ability to provide informed consent, with no severe comorbid conditions that would preclude study procedures (e.g. unable to provide stool sample or undergo blood draws).

Exclusion Criteria:

1. Prior systemic therapy for metastatic PDAC.
2. Current use of long-term antibiotics or probiotics that could significantly alter the gut microbiome unless they are willing to pause these interventions (to avoid confounding in microbiome analysis).
3. Co-existing active malignancy that could confound metabolomic or immune readouts, unless it is a low-grade, early cancer in remission.