Cancer of the pancreas and pancreatic cystic lesions

Published on 09/04/2015 by admin

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Last modified 09/04/2015

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Chapter 13 CANCER OF THE PANCREAS AND PANCREATIC CYSTIC LESIONS

• Pancreatic cancer is an aggressive cancer with a low survival time: 10%–15% survival at 5 years.

• The major risk factors include smoking, chronic pancreatitis, hereditary pancreatitis and dietary factors.

• Most patients present with symptoms late in the course of the disease.

• The classical presentation is painless obstructive jaundice, weight loss and back pain.

• Imaging plays a vital role in diagnosis. Procedures include endoscopic ultrasound (EUS), contrast enhanced computed tomography (CE-CT) scan, magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), endoscopic retrograde cholangiopancreatography (ERCP). It is often necessary to use a combination of modalities to obtain a diagnosis and select treatment.

• Early surgical resection is the only potentially curative treatment for pancreatic cancer.

• Gemcitabine is the choice of chemotherapeutic drugs.

• As a result of advances in imaging there is an increased prevalence of asymptomatic pancreatic cysts.

• Cysts are either inflammatory (pseudocysts), benign (serous cystadenomas), premalignant (mucinous cysts) or malignant (cystadenocarcinoma).

• Mucinous cystic neoplasms (MCNs) are considered premalignant and encompass intraductal papillary mucinous neoplasms (IPMN) and mucinous cystadenoma.

• Microcystic morphology is the hallmark of serous lesions.

• MCNs are characterised by proliferation of the epithelium of the pancreatic duct with various degrees of mucin hypersecretion and a dilated main pancreatic duct.

• The treatment of MCNs depends on the presence or absence of symptoms and the surgical risk to the patient.

• Patients are best managed in specialised centres.

PANCREATIC CANCER

Pancreatic cancer is an aggressive cancer with a low survival rate. It is the fifth most common cause of cancer related deaths in the USA. This is due to the advanced nature of the disease at diagnosis.

Risk factors

The major risk factors are: increasing age, smoking, chronic pancreatitis, hereditary pancreatitis (40% risk of developing cancer by the age of 70 years), recent onset of diabetes mellitus (particularly in patients over the age of 50 years) and dietary factors (a high intake of fat and/or meat),

Screening tests

For persons at high risk, screening should be initiated 10 years before the age at which pancreatic cancer was first diagnosed in families with syndromes and after the age of 35 in hereditary pancreatitis. At present, the strategy involves measurements of the tumour-associated antigen CA 19-9 and spiral CT followed by endoscopic ultrasound if CT results are not diagnostic.

Clinical features

Most patients present with symptoms late in the course of the disease. Tumours in the head of the pancreas present with symptoms earlier than those in the distal gland which are characterised by a ‘silent’ presentation, often with metastases. The classical presentation is painless obstructive jaundice, weight loss and back pain. Other presentations include nausea and vomiting, late-onset diabetes mellitus without obesity, acute/chronic pancreatitis, acute cholangitis, duodenal obstruction and deep vein thrombosis.

Clinical signs include evidence of weight loss, jaundice, hepatomegaly, a palpable gall bladder, Troisier’s sign (enlarged left supraclavicular lymph nodes), an abdominal mass and ascites. In patients suspected of having a pancreatic malignancy, weight loss, hyperbilirubinaemia and an increased CA 19-9 may be highly predictive of pancreatic malignancy. Surgical exploration should be considered in these patients even in the absence of a preoperative diagnosis.

Diagnostic methods

Laboratory investigations

Laboratory investigations include a complete blood count, liver function tests, clotting profile and CA 19-9.

Imaging

Endoscopic ultrasound (EUS)

Has a high sensitivity and specificity. It can be combined with fine needle aspiration (FNA) to obtain biopsies. However, it is less effective in assessing nodal involvement.

Contrast-enhanced computed tomography (CE-CT) scan

The method of choice for diagnosis and staging. A correct diagnosis can be made in 97% of patients. Spiral CE-CT has almost 100% accuracy in predicting unresectable disease. Tumors involving critical structures (e.g. portal vein, hepatic or coeliac artery) are not resectable.

Magnetic resonance imaging (MRI)

Results in the same efficacy as CE-CT and is used if patients cannot tolerate intravenous contrast.

Magnetic resonance cholangiopancreatography (MRCP)

Provides images of the pancreatic and biliary duct systems. The procedure does not involve radiation and uses an iodine-free contrast agent.

Endoscopic retrograde cholangiopancreatography (ERCP)

Both diagnostic and therapeutic. Biopsies or brush cytology for diagnosis can be obtained and stents placed to relieve obstruction. At the initial ERCP, an attempt should be made to decompress the biliary tree, especially if the patient is symptomatic.

Positron emission tomography (PET)

Can differentiate inflammatory conditions from metastatic tumours.

Laparoscopy

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