Investigations and diagnosis

• full blood count
• may reveal a normochromic anaemia or thrombocytosis or both
• raised serum bilirubin, alkaline phosphatase and γ‑glutamyltransferase in obstructive jaundice (serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) may also be raised to a lesser extent)
• may be impaired glucose tolerance or diabetes
• tumour markers
• carbohydrate 19-9 (CA19-9) - also known as sialylated Lewis (a) antigen
• although most widely used serum tumor marker it is not specific for pancreatic cancer (a sensitivity of 80% and specificity of 73% for pancreatic cancer
• is a useful to assess response to treatment and as a surveillance tool after treatment
• imaging
• initial examination
  • abdominal ultrasound –
    • double duct sign - bile duct dilation (>7 mm, or >10 mm if previous cholecystectomy) with pancreatic duct dilation (>2 mm) may be a sign of pancreatic cancer
    • other findings - liver metastases and ascites
• further evaluations
  • triple phase computed tomography preceded by non-contrast computed tomography
    • best method for detecting pancreatic neoplasms and assessing resectability
  • endoscopic ultrasound
    • useful especially for small tumours (<3cm)
    • can detect involvement of loco regionl lympnodes
    • also used to guide fine needle aspiration (FNA) for cytological evaluation of lesions in which there is diagnostic uncertainty
  • positron emission tomography (PET) combined with CT (PET-CT)
    • it is more sensitvie in detecting pancreatic cancer and extra hepatic metastasis
  • MRI combined with magnetic resonance cholangiopancreatography (MRCP)
  • endoscopic retrograde cholangiopancreatography (ERCP)
    • is an effective way of confiming pancreatic adenocarcinoma with sensitivity of 90-95%
    • an invasive procedure whith 5-10% isk of significant complications hence reserved for therapeutic procedure for biliary obstruction or for the diagnosis of unusual pancreatic neoplasms

NICE state that with respect to diagnosis of pancreatic cancer:

• Diagnosis:
  • People with obstructive jaundice
    • if obstructive jaundice and suspected pancreatic cancer, offer a pancreatic protocol CT scan before draining the bile duct.
    • if the diagnosis is still unclear, offer fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT) and/or endoscopic ultrasound (EUS) with EUS-guided tissue sampling.
    • take a biliary brushing for cytology if:
      • endoscopic retrograde cholangiopancreatography (ERCP) is being used to relieve the biliary obstruction and
      • there is no tissue diagnosis
        
        
  • People without jaundice who have pancreatic abnormalities on imaging
    • a pancreatic protocol CT scan should be offered to people with pancreatic abnormalities but no jaundice.
    • if the diagnosis is still unclear, offer FDG-PET/CT and/or EUS with EUS-guided tissue sampling.
    • if cytological or histological samples are needed, offer EUS with EUS-guided tissue sampling

Reference:

• (1) Bond-Smith G et al. Pancreatic adenocarcinoma. BMJ. 2012;344:e2476
• (2) NICE (February 2018). Pancreatic cancer