Part of the TeachMe Series

Pancreatic Cancer

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Last updated: August 3, 2020
Revisions: 29

Last updated: August 3, 2020
Revisions: 29

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Introduction

Pancreatic cancer will typically refer to ductal carcinoma of the pancreas, which comprises up to 90% of primary pancreatic malignancies. The remaining number can be divided into exocrine tumours (such as pancreatic cystic carcinoma) and endocrine tumours (derived from islet cells of the pancreas).

Pancreatic cancers have a high mortality rate, being the 4th most common cause of cancer death in the UK. It is rare under 40 years of age, with 80% of cases occurring between 60-80yrs. It is rarely diagnosed early enough for curative treatment.

In this article, we shall look at the risk factors, investigations and management of a patient with pancreatic cancer.

Pathophysiology

The most common type of pancreatic cancer is ductal carcinoma (90% of primary pancreatic malignancies). Other rarer forms include cystic tumours, ampullary cell tumours and islet cell tumours, which all often have a much better prognosis.

As the cancer spreads, direct invasion of local structures typically involves the spleen, transverse colon, and adrenal glands. Lymphatic metastasis typically involves regional lymph nodes, liver, lungs, and peritoneum. Metastasis is common at the time of diagnosis.

Fig 1 - Pancreatic cancer can spread directly to surrounding structures, such as the spleen, transverse colon and adrenal gland.

Figure 1 – Pancreatic cancer can spread directly to surrounding structures, such as the spleen, transverse colon and adrenal gland.

Risk Factors

There are few clear risk factors for the development of carcinoma of the pancreas. Those that have been identified include smoking and chronic pancreatitis. There may also be a hereditary element, as 7% of patients have a family history of the disease.

Late onset diabetes mellitus is an additional risk factor. Those diagnosed with diabetes >50yrs have an 8x greater risk of developing pancreatic carcinoma in the following three years than the general population.

Clinical presentation

Approximately 80% of cases of pancreatic carcinoma are unresectable at diagnosis, testament to the late and often vague and non-specific nature of its presentation.

The specific clinical features* can depend on the site of the tumour:

  • Obstructive jaundice – due to compression of the common bile duct (present in 90% of cases at time of diagnosis), typically painless
  • Weight loss – due to the metabolic effects of the cancer, or secondary to exocrine dysfunction
  • Abdominal pain (non-specific) – due to invasion of the coeliac plexus or secondary to pancreatitis

Less common presentations include acute pancreatitis or thrombophlebitis migrans (a recurrent migratory superficial thrombophlebitis, caused by a paraneoplastic hypercoagulable state). 

*Tumours of the tail of the pancreas have an insidious course and often not symptomatic until a late stage

On examination, patients may appear cachecticmalnourishedand jaundiced. On palpation, an abdominal mass in the epigastric region may be felt, as well as an enlarged gallbladder (as per Courvoisier’s Law)

Courvoisier’s Law

Courvoisier’s law states that in the presence of jaundice and an enlarged/palpable gallbladder, malignancy of the biliary tree or pancreas should be strongly suspected, as the cause is unlikely to be gallstones.

This sign may be present if the obstructing tumour is distal to the cystic duct. In reality an enlarged gallbladder is present in less than 25% of patients with pancreatic cancer.

Differential Diagnosis

Pancreatic cancer often presents with vague, non-specific features. The differential diagnoses are vast and include:

  • Causes of obstructive jaundice – gallstone disease, cholangiocarcinoma, benign gallbladder stricture
  • Causes of epigastric abdominal pain – gallstones, peptic ulcer disease, gastric carcinoma, acute coronary syndrome

Investigations

Laboratory tests

Any suspected pancreatic cancer should warrant initial blood tests, including FBC (anaemia or thrombocytopenia) and LFTs (raised bilirubin, alkaline phosphatase, and gamma-GT, showing an obstructive jaundice picture).

CA19-9 is a tumour marker with a high sensitivity and specificity for pancreatic cancer, yet its role is in assessing response to treatment rather than for initial diagnosis.

Imaging

The initial imaging for pancreatic cancer is commonly an abdominal ultrasound, which may demonstrate a pancreatic mass or a dilated biliary tree (as well as potential hepatic metastases and ascites if very late stage disease).

CT imaging (using a pancreatic protocol, Fig. 2) is both the most important investigation in terms of diagnosis, but also the most prognostically informative as it can stage disease progression. A chest-abdomen-pelvis CT scan will be further required once pancreatic cancer has been diagnosed for staging; a PET-CT scan may be warranted in those with localised disease on CT who will be having cancer treatment

Endoscopic ultrasound (EUS) may be subsequently be used to guide fine needle aspiration biopsy in order to histologically evaluate the lesion, if the diagnosis is still unclear. ERCP can also be used to access the lesion for biopsy or cytology, if in a suitable location*.

*A biliary brushing for cytology if ERCP is being used to relieve the biliary obstruction and there is no tissue diagnosis.

Fig 2 - A adenocarcinoma located in the pancreatic head, identified on CT scan

Figure 2 – A adenocarcinoma located in the pancreatic head, identified on CT scan

Management

Surgery

The only curative management option is currently radical resection:

  • For patients with tumours of the head of the pancreas, the most common surgery with curative intent is pancreaticoduodenectomy, also known as a Whipple’s procedure
    • Pylorus-preserving resections can be attempted in certain cases
  • For patients with tumours of the body or tail of pancreas, a distal pancreatectomy can often be performed

Absolute contraindications for surgery include peritoneal, liver and distant metastases. There is a high morbidity associated with these procedures (up to 40%) and specific complications include formation of a pancreatic fistula, delayed gastric emptying, and pancreatic insufficiency.

Cochrane review found that pancreatic resection increases survival and reduces costs compared to palliative treatments in patients with locally advanced pancreatic cancer and venous involvement, assuming there is sufficient clinical expertise available.

Whipple’s Procedure

A Whipple’s procedure involves the removal of the head of the pancreas, the antrum of the stomach, the 1st and 2nd parts of the duodenum, the common bile duct, and the gallbladder.

All viscera removed in the operation are done so due to their common arterial supply (the gastroduodenal artery), shared by the head of the pancreas and the duodenum.

Following this, the tail of the pancreas and the hepatic duct are attached to the jejunum, allowing bile and pancreatic juices to drain into the gut, whilst the stomach is subsequently anastomosed with the jejunum allowing for the passage of food.

Fig 3 - Pancreaticoduodenectomy (Whipple's procedure). A: Pre-procedure, B: Post-procedure.

Figure 3 – Pancreaticoduodenectomy (Whipple’s procedure). A: Pre-procedure, B: Post-procedure

Chemotherapy

Adjuvant chemotherapy, generally with 5-flourouracil, is recommended after surgery as it has been demonstrated to improve survival following the ESPAC-1 trial*.

In metastatic disease the use of FOLFIRINOX regime (folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin) is advised in those with a good performance status, however has yielded only modest improvements in survival; gemcitabine therapy can be considered for people with locally advanced pancreatic cancer who are not well enough to tolerate FOLFIRINOX.

*ESPAC-1 also demonstrated patients treated with adjuvant chemoradiotherapy had worse outcomes overall than those treated with adjuvant chemotherapy alone.

Palliative Care

The majority of patients with pancreatic cancer are not candidates for curative surgery, but instead require palliative care involvement.

Obstructive jaundice and associated pruritis can be relieved with the insertion of a biliary stent, either via ERCP or percutaneously.

Palliative chemotherapy, such as with a gemcitabine-based regime, can be trialled in patients with a reasonable performance status.

Exocrine insufficiency is common in advanced disease or those who have had significant excision of the pancreas, lead to malabsorption and steatorrhoea; this can initially be treated with enzyme replacements (including lipases), such as Creon®.

Prognosis

Pancreatic cancer has a high metastatic capacity even in small tumours. The prognosis in pancreatic cancer remains very poor, with overall 5-year survival rate <5%.

Key Points

  • Pancreatic cancer will often present with a combination of obstructive jaundice, abdominal pain, or weight loss
  • Most cases are initially detected on CT scan, however require tissue diagnosis through biopsy; CA19-9 is a tumour marker used for monitoring disease progression
  • Definitive management is surgical resection, often with adjuvant chemotherapy
  • Pancreatic cancer has a 5-year survival rate of less than 5%

Endocrine Tumours of the Pancreas

Endocrine tumours of the pancreas may be functional or non-functional. Functional tumours actively secrete hormones and their signs and symptoms are related to this, whilst non-functional tumours do not secrete active hormones and clinical features are related purely to their malignant spread.

Endocrine tumours of the pancreas are often associated with multiple endocrine neoplasia 1 syndrome (MEN1); MEN1 typically consists of hyperparathyroidism, endocrine pancreatic tumours, and pituitary tumours (most commonly prolactinomas).

Clinical Features

Cell Type Secreted Hormone (name of tumour) Normal Physiological Function Features of Functional Tumour
G cells Gastrin (gastrinoma) Stimulates the release of gastric acid Zollinger-Ellison syndrome, resulting in severe peptic ulcers, refractory to medical treatment, with diarrhoea and steatorrhoea
α Cells Glucagon (Glucagonoma) Increase blood glucose concentration Hyperglycaemia, diabetes mellitus, and necrolytic migratory erythema
β Cells Insulin (insulinoma) Decrease blood glucose concentration Symptomatic hypoglycaemia, such as sweating or changed mental state, improving with consumption of carbohydrates
δ Cells Somatostatin (Somatostatinoma) Inhibits the release of GH, TSH and prolactin from the anterior pituitary, and of gastrin Diabetes mellitus, steatorrhoea, gallstones (due to inhibition of cholecystokinin), weight loss, and achlorhydria (due to gastrin inhibition)
Non-islet cells Vasoactive intestinal peptide (VIPoma) Secretion of water and electrolytes into the gut. Relaxation of enteric smooth muscle. Prolonged profuse watery diarrhoea, severe hypokalaemia, and dehydration (also known as Verner-Morrison syndrome)

Table 1 – Endocrine tumours of the pancreas

Investigation

All cases should be discussed at a multi-disciplinary team meeting where management can be guided. Certain blood tests can be sent, depending on the suspected subtype (Table 1)

Pancreatic NETs are best investigated with a combination of CT imaging, MRI imaging, and / or Endoscopic Ultrasound. Intra-arterial calcium with digital subtraction angiography can also be used in the localisation and assessment of insulinomas and gastrinomas.

Management

Small non-functional well differentiated pancreatic NETs (<1cm) can simply be observed. Larger or functioning tumours are resected, with any distant metastatic disease also resected if the tumour is low grade and the metastases is low volume.

Somatostatin analogues can be used to control and ameliorate the effects of hormonal hypersecretion (even in the case of somatostatinomas).