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types of cancer

Pancreatic Cancer

Overview

Pancreatic cancer is a malignant neoplasm originating from transformed cells arising in tissues forming the pancreas. The most common type of pancreatic cancer, accounting for 95% of these tumours, is adenocarcinoma (tumours exhibiting glandular architecture on light microscopy) arising within the exocrine component of the pancreas. A minority arise from islet cells, and are classified as neuroendocrine tumours. The signs and symptoms that eventually lead to the diagnosis depend on the location, the size, and the tissue type of the tumour, and may include abdominal pain, lower back pain and jaundice.

More dangerous, or malignant tumours form when the cancer cells migrate to other parts of the body through the blood or lymph systems. When a tumour successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process itself is called metastasis, and the result is a more serious condition that is very difficult to treat.

The most common type of pancreatic cancer, accounting for 95% of these tumours, is adenocarcinoma (tumours exhibiting glandular architecture on light microscopy) arising within the exocrine component of the pancreas. A minority arise from islet cells, and are classified as neuroendocrine tumours. The signs and symptoms that eventually lead to the diagnosis depend on the location, the size, and the tissue type of the tumour, and may include abdominal pain, lower back pain and jaundice.

When a tumour successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process itself is called metastasis, and the result is a more serious condition that is very difficult to treat.

Symptoms

Early pancreatic cancer often does not cause symptoms, and the later symptoms are usually nonspecific and varied. Therefore, pancreatic cancer is often not diagnosed until it is advanced. Common symptoms include:

  • Pain in the upper abdomen that typically radiates to the back
  • Heartburn
  • Poor appetite or nausea and vomiting
  • Diarrhoea, loose stools
  • Significant weight loss
  • Painless jaundice (yellow tint to whites of eyes or yellowish skin, possibly in combination with darkened urine). The jaundice may be associated with itching as the salt from excess bile can cause skin irritation
  • Pulmonary embolisms due to pancreatic cancers producing blood clotting chemicals
  • Diabetes mellitus, or elevated blood sugar levels. Many patients with pancreatic cancer develop diabetes months to even years before they are diagnosed with pancreatic cancer, suggesting that the onset of diabetes in an elderly individual may be an early warning sign of pancreatic cancer
  • Signs of cancer metastasis. Typically, pancreatic cancer first metastasises to regional lymph nodes, and later to the liver or to the peritoneal cavity and rarely, to the lungs; it rarely metastasises to bone or brain.
  • Causes

    Although pancreatic cancer is not yet fully understood, several risk factors and causes that have been identified may increase your chance of developing it:

    Ageing Pancreatic cancer can affect people of any age, but it mainly affects people aged 50 to 80. Around 63% of people diagnosed with cancer of the pancreas are over 70.

    Smoking Smoking is associated with almost a third of all pancreatic cancer cases. Smoking cigarettes, cigars or chewing tobacco can all increase your risk of developing cancer of the pancreas. This is because tobacco smoke contains harmful toxins and chemicals that can cause irritation and inflammation (swelling) in the tissues and organs within your body.

    Chronic Pancreatitis Chronic pancreatitis (long-term inflammation of the pancreas) will increase your risk of pancreatic cancer. Although very uncommon, patients with hereditary (inherited) pancreatitis have a particularly high risk of pancreatic cancer, especially from the age of 40.

    Diagnosis

    It is important to note that pancreatic cancer is not just one disease. There are many types of pancreatic tumours, each with its own unique prognosis and treatment recommendations. In the diagnosis of pancreatic cancer, the doctor may conduct the following tests:

    Medical History and Physical Examination: A series of tests may be necessary to make a definite diagnosis. The doctor will first start by asking about the patient’s medical history and any physical complaints or symptoms, specifically recent weight loss, pain and changes in appetite, bowel patterns or skin colour. The doctor will then complete a thorough physical exam, which will include palpation and observation of the chest and abdomen.

    Lab Tests: Blood specimens may be collected and less commonly, urine or stool samples may also be asked for. Of particular interest to the doctor is the level of bilirubin and liver enzymes in a patient’s blood, which measures liver and pancreas function.

    Another blood test commonly performed is CA19-9 (carbohydrate antigen 19-9). CA19-9 is referred to as a ‘tumour marker’ which is a chemical substance in the body that may be found at higher levels if cancer is present. An elevated CA19-9 test by itself is not used to make the diagnosis of pancreatic cancer, as it can be elevated in a variety of other conditions, such as pancreatitis or cirrhosis of the liver, and some people with pancreatic cancer do not show this marker at all. CA 19-9 however can be used as a tool to help evaluate the effectiveness of a cancer therapy by comparing the levels before and during treatment.

    Ultrasound: Ultrasound uses a machine that emits high-frequency sound waves to create images of the organs inside the body. An abdominal ultrasound examines the liver, gallbladder, spleen, pancreas and kidneys, and can help identify abnormal structures or tissue.

    Computed Tomography (CT) Scan: This is a non-invasive method of examining internal organs that captures a series of thin x-ray images of the inside of the body. CT scans can help detect tumours and determine whether it has spread to other parts of the body, such as the liver.

    There are different types of CT scans and special techniques that can be done to create more detailed images of the pancreas. Some places offer a three-dimensional CT scan, often referred to as a ‘spiral’ or ‘helical’ scan, which creates extremely detailed images of the pancreas and nearby blood vessels and structures to help determine treatment decisions.

    Endoscopic Ultrasound (EUS): This is a procedure that allows a specially trained doctor, typically a gastroenterologist, to view the oesophagus, stomach and the first portion of the small intestine, as well as adjacent organs including the liver and pancreas. While the patient sleeps, a thin flexible tube called an endoscope is passed through the mouth into the stomach and small intestine. At the end of the tube is an ultrasound probe that emits sound waves that create images of the abdominal organs.

    If unusual masses are detected, the doctor may collect a specimen of tissue at the time of the procedure during a biopsy. The use of EUS can decrease the likelihood that a patient will need to go to the operating room for surgery.

    Endoscopic Retrograde Cholangiopancreatography (ERCP): This procedure uses an endoscope – a long, flexible, lighted tube connected to a computer and TV monitor. The doctor guides the endoscope through the patient’s stomach and into the small intestine. ERCP combines two imaging techniques: ‘endoscopy’ the direct visualisation of internal structures and ‘fluoroscopy’ a live action x-ray method. These two techniques allow the doctor to view images of the liver, gall bladder and pancreas ducts, which can help detect a narrowed or blocked duct.

    Further tests, such as a biopsy, can pinpoint the cause of a narrowed or blocked duct. If a duct is narrowed or blocked by a tumour, a plastic or metallic stent can be placed across the blockage. The stent is designed to expand and reopen the duct to allow bile juices to flow freely.

    Magnetic Resonance Cholangiopancreatography (MRCP): MRCP uses radio waves and a powerful magnet linked to a computer to visualise the biliary and pancreatic ducts in a non-invasive manner. These pictures can show the difference between normal and diseased tissue and can also detect bile duct obstruction.

    MRCP may be performed in patients who cannot have an Endoscopic Retrograde Cholangiopancreatography (ERCP) or may also prevent unnecessary invasive procedures.

    Biopsy: A biopsy allows a doctor to collect a small amount of tissue. A pathologist then uses a microscope to examine the tissue and identify the types of cells collected.

    Tissue can be collected at the time of an endoscopic ultrasound or endoscopic retrograde cholangiopancreatography. A biopsy can also be performed under the guidance of a CT scan. If necessary, a biopsy can be performed at the time of abdominal open surgery.

    There are two methods frequently used to collect tissue for a biopsy. A Fine Needle Aspiration (FNA) utilises a very narrow needle. A core needle biopsy uses a larger needle. Both methods have advantages and risks.

    If cancer is suspected to have spread, or metastasised, it is preferable to biopsy the tumour than the pancreas itself. A specially trained doctor can then determine the best method to use. It is also important to note that if all of your other test results suggest cancer, you may not need a biopsy before you have treatment.

    Treatment

    Treatment for pancreatic cancer depends on the stage and location of the cancer. Following are the treatments that a doctor will recommend depending on the stage of cancer.

    SURGERY Surgery may be an option if the cancer is confined only to the pancreas. Operations used in people with pancreatic cancer include:

    • Surgery for tumours in the pancreatic head: If the cancer is located in the head of the pancreas, whipple procedure is used by the doctor. It involves removing the head of the pancreas, as well as a portion of the small intestine (duodenum), the gallbladder and part of the bile duct. Part of the stomach may also be removed. Finally, the surgeon reconnects the remaining parts of the pancreas, stomach and intestines to allow the patient to digest food.
    • Surgery for tumours in the pancreatic tail and body: Surgery to remove the tail of the pancreas or the tail and a small portion of the body is called distal pancreatectomy. The surgeon may also remove the spleen. Surgery carries a risk of bleeding and infection.

    RADIATION THERAPY Radiation therapy uses high-energy beams, such as x-rays and protons, to destroy cancer cells. The patient may receive radiation treatments before or after cancer surgery, often in combination with chemotherapy. Or, the doctor may recommend a combination of radiation and chemotherapy treatments when your cancer can’t be treated surgically.

    Radiation therapy usually comes from a machine that moves around you, directing radiation to specific points on the body (external beam radiation).

    CHEMOTHERAPY

    Chemotherapy uses drugs to help kill cancer cells. Chemotherapy can be injected into a vein or taken orally. Depending on the extent of cancer, the patient may receive only one chemotherapy drug, or you may receive a combination of chemotherapy drugs.

    Chemotherapy can also be combined with radiation therapy (chemoradiation). Chemoradiation is typically used to treat cancer that has spread beyond the pancreas, but only to nearby organs. This combination may also be used after surgery to reduce the risk that pancreatic cancer may recur.

    In people with advanced pancreatic cancer, chemotherapy may be used alone or it may be combined with targeted drug therapy.

    TARGETED THERAPY Targeted therapy uses drugs that attack specific abnormalities within cancer cells. There are targeted drugs which blocks chemicals that signal cancer cells to grow and divide. Such drugs are usually combined with chemotherapy for use in people with advanced pancreatic cancer.

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