This is a prospective observational study which aims to evaluate;

The prevalence of pancreatic insufficiency in patients with pancreatic malignancies (adenocarcinoma and neuroendocrine tumours).

The most appropriate diagnostic strategy. The impact that an adequate diagnosis and treatment may have on patients' outcome.

Patients will prospectively receive a full nutritional assessment, pancreatic enzyme insufficiency (PEI) diagnosis and dietician education. This assessment will be performed as an outpatient in parallel with the medical oncology team, by the research dietician. This study will be performed in two steps (summarized in Figure 2);

Step-1 | A prospective cross-sectional assessment of the prevalence of PEI-related symptoms in up to n=150 patients with pancreatic malignancy (this will be termed 'the demographic cohort'). A sub-set of these patients (n=50) will be tested to elucidate the most efficient diagnostic panel for PEI in pancreatic malignancy (this will be termed 'the diagnosis cohort').

Step-2 | A prospective longitudinal validation of the diagnostic panel designed and tested in Step-1 and evaluation of dietician intervention (including PERT) and its impact in weight loss, symptom evolution, chemotherapy receiving rate, Quality of Life and overall survival (this will be termed 'the follow-up cohort' and will include up to n=50 patients).

All patients included in both steps will have a full nutritional assessment at baseline, and PERT treatment (as per standard of care if considered appropriate). Patients in the follow-up cohort will be reviewed (at least every 3 months for a maximum of 6 months since study entry) by dietician for further intervention and assessment.

Inclusion Criteria:

• Patients with histologically/cytologically-proven or clinically-suspected (by specialist MDT) pancreatic malignancy including pancreatic ductal adenocarcinoma or pancreatic NET.
• Patients to be seen in the Medical Oncology HPB and NET team clinic for assessment
• Age ≥18 years with no upper age limit
• Patients must be able to give informed consent; Written consent will be required for patients to be included within the diagnostic cohort Verbal consent only will be required for patients to be included within the demographic cohort and the follow-up cohort

Additional cohort-specific criteria;

• Patients will be recruited into three different cohorts with differing levels of participation (termed demographic, diagnostic and follow-up). Patients will not be recruited into the follow-up cohort until recruitment of both demographic and diagnosis cohorts are complete and the interim analysis has been performed.
• Demographic cohort | All patients referred for consideration of cancer treatment options will be eligible. Patients will need to give verbal informed consent.
• Diagnosis cohort | Patients who are already consented for being included into the demographic cohort and who will be attending at least to one follow-up appointment and are considered to be fit enough for diagnostic assessment will be eligible. Patients will need to give written informed consent.
• Follow-up cohort | All patients referred for consideration of options of cancer treatment will be included; patients with a minimum of 3 months of follow-up will be included in the final analysis. Patients will need to give verbal informed consent.

Exclusion Criteria:

- As long as the inclusion criteria are fulfilled, there are no exclusion criteria.

Patients with histologically/cytologically-proven or clinically-suspected (by specialist MDT) pancreatic malignancy including pancreatic ductal adenocarcinoma or pancreatic NET.