Bowel cancer is the name for cancers that arise in the large intestine or rectum. Also known as colon cancer or colorectal cancer, bowel cancer can interfere with bowel function and spread to other parts of the body, such as the liver and lungs.…
What is pancreatic cancer?
Pancreatic cancer occurs when abnormal cells grow uncontrollably in the pancreas, an organ located behind the stomach. The pancreas produces enzymes for digestion and hormones for blood glucose regulation.
These abnormal cells in the pancreas can grow to form a cancer, which can spread to other parts of the body.
The cause of pancreatic cancer, as with other cancers, is due to damage to cellular DNA. This damage results in uncontrolled growth of damaged cells, which leads to formation of a cancer. A cancer can grow into nearby tissue, or cells can break off and spread throughout the body via the bloodstream or lymphatic system. The exact causes of this cellular damage in the pancreas are not known.
Risk factors that increase the chances of developing pancreatic cancer include:
- Smoking - it is associated with a two-to-threefold increase in the risk of developing pancreatic cancer;
- Age - people between 60-80 years of age account for more than 80% of cases;
- Chronic pancreatitis - inflammation of the pancreas is associated with cancer when it occurs over the long-term. The exact reason for this is unclear, but it is possible that prolonged inflammation causes damage to cellular DNA;
- Stomach surgery - the surgical removal of part of the stomach, due to a stomach ulcer or a cancer, is associated with an increased risk of developing pancreatic cancer, and;
- Diets high in meat, cholesterol and food preservatives.
Exocrine tumors are the most common type of pancreatic cancer. They are cancers of the exocrine pancreas, which is where the exocrine glands are located. These glands produce the pancreatic enzymes that are released into the intestine.
Adenocarcinoma cancers form in the exocrine glands and account for about 95% of all exocrine pancreatic cancers.
Less common types of pancreatic cancers
There are several other types of exocrine cancers that form in areas around the exocrine glands rather than in the glands themselves.
Endocrine tumors arise from the endocrine glands, originating in the cells that produce hormones. They are also called neuroendocrine tumors and are an uncommon type of pancreatic cancer. Endocrine tumors are defined as functional if they secrete hormones and non-functional if they do not.
Some types of endocrine tumors include:
- Insulinomas - originate in cells that produce insulin, the hormone that reduces blood glucose levels;
- Gastrinomas - originate in cells that make gastrin, a hormone that stimulates production of stomach acid;
- Glucagonomas - originate in alpha cells that produce glucagon, a hormone that raises blood glucose levels;
- Somatostatinomas - originate in cells that make somatostatin, a hormone involved in the regulation of other hormones;
- VIPomas - originate in cells that make vasoactive intestinal peptide, a neurotransmitter that has several regulatory functions, and;
- PPomas - originate in cells that produce pancreatic polypeptide, a hormone released in response to food ingestion.
Stages of pancreatic cancer
Treatment outcomes can vary greatly, depending on the stage of cancer. Cancer is staged according to its size and location, and whether it has spread to nearby or distant lymph nodes or organs throughout the body.
The cancer is located in the pancreas and has not spread.
The cancer has spread to nearby lymph nodes or structures near the pancreas, but has not spread to other organs.
The cancer has spread to nearby major arteries, with or without the lymph node being affected.
The cancer has spread to other organs such as the lungs or liver.
Signs and symptoms
Pancreatic cancer is uncommon and many of the following symptoms may also be due to other causes.
Jaundice and pale stools
If there is a blockage in a bile duct, it can cause jaundice, the symptoms of which include yellowing of the eyes and skin. It can also cause pale stools, if insufficient bile is present in the intestines to give stool its color.
Nausea and vomiting
A blockage of the pancreatic or bile ducts can cause inflammation of the pancreas and put pressure on surrounding organs, which can lead to nausea and vomiting.
Loss of appetite and weight loss
Loss of appetite can be associated with nausea and vomiting. Weight loss can result from the cancer blocking the enzymes needed to digest food.
Unexpected onset of diabetes
Methods for diagnosis
Scans used in the diagnosis of pancreatic cancer include:
- Computerized tomography (CT) scan - can help detect pancreatic cancer;
- Magnetic resonance imaging (MRI) - can provide detailed images of the pancreas, in particular the pancreatic duct, and;
- Positron emission tomography (PET) - can help to assess the tumor and its spread.
CA19.9 is a protein associated with pancreatic cancer, but its presence does not necessarily mean you have pancreatic cancer and it is not elevated in all forms of pancreatic cancer. It is mainly used to track the progress of treatment rather than to diagnose a tumor.
Pancreatic cancer can affect the function of the liver and kidneys, so tests are performed to check their functionality.
Procedures performed to diagnose pancreatic cancer include:
- Endoscopy - involves the insertion of a long and narrow telescopic camera down the throat into the digestive system. This may be used to assess blocked pancreatic or bile ducts and reopen them with stents if possible;
- Laparoscopy - involves making a small incision in the abdomen so a camera can be inserted to see the internal organs. This may be done to determine the extent of the spread of pancreatic cancer and to do a biopsy, and;
- Tissue biopsy - involves removing a sample of pancreatic tissue for examination by a pathologist.
Types of treatment
Surgery is used to remove a cancer that has not spread. If you have pancreatic cancer and are fit for major surgery, your doctor will perform a procedure called Whipple's resection. This is where a portion of the gall bladder, bile ducts and sometimes stomach are removed.
Another type of procedure, called a distal pancreatectomy, involves removing the cancer and surrounding tissue from the tail end of the pancreas. If the cancer cannot be removed, other forms of surgery can be used as a means of relieving symptoms. For example, stents can be inserted into the bile and pancreatic ducts to keep them open.
Other therapies can be used in addition to surgical treatments to further improve treatment outcomes. They may be given before surgery (neoadjuvant therapy) and/or after surgery (adjuvant therapy). When given before surgery, they aim to reduce the size, and therefore stage, of the cancer. When given after surgery, they aim to help prevent the cancer returning. These non-surgical treatments include chemotherapy, radiotherapy, hormone therapy or a combination of these.
Occasionally, these therapies may be used if individuals are not suitable for surgical treatment. Often, in these situations, the aim of treatment is to control symptoms, and are not necessarily for cure. The treatment options and aims can differ, based upon the individual, the stage and type of cancer. Your doctor can help explain this information in more detail.
Chemotherapy works by damaging cancer cells and stopping their reproduction. Various medications can be used, which can be administered intravenously or orally. They are often given in cycles, with intervening rest periods, to help reduce toxic side effects.
Side effects occur because chemotherapy can also affect healthy cells. Your doctor will monitor your dosage carefully to achieve the best therapeutic effect.
Radiotherapy focuses X-rays on the area where the cancer is located. Radiotherapy can be used alone, or in addition to surgery and/or chemotherapy.
Hormone therapy is sometimes used to treat advanced pancreatic cancer, if the cancer cells are found to carry a particular hormone receptor. For example, some pancreatic cancers have estrogen receptors and tamoxifen is a medication that can be used to block that receptor, potentially slowing the growth of the tumor.
Some people diagnosed with cancer seek out complementary and alternative therapies. None of these therapies are proven to cure cancer, but some can help people feel better when used together with conventional medical treatment. It is important to discuss any additional treatments with your doctor before starting them.
Treatment side effects
Side effects of treatment for pancreatic cancer can include:
- Nausea, vomiting and fatigue;
- Altered bowel habits, such as constipation or diarrhea;
- Joint and muscle pain;
- Temporary hair loss from the head and body, and;
- Tingling in the hands and feet - some chemotherapeutic agents can affect the nerves. It is important to tell your doctor if you develop these symptoms.
Advanced pancreatic cancer
Metastasis is when the cancer spreads to other parts of the body through the bloodstream and lymphatic system. The metastasized cancer damages the function of an affected organ or body part.
The outlook for pancreatic cancer depends on the type and stage of cancer, however the overall survival rates are usually low, as it is most often diagnosed at an advanced stage.
It is important to remember survival rates are only an indication, and are based upon the averages of previously treated patients. It is not an absolute prognosis for an individual. It is often difficult to accurately predict an individual's cure or survival rate. Constant advances in treatment are continually improving these statistics.
As pancreatic cancer progresses, the aim of treatment shifts from extending life to minimizing pain, with palliative care available for terminal patients.