Pancreatic cancer: Symptoms, Function of your Pancreas, Causes, Types, Risk factors, Complications and Prevention


Pancreatic cancer begins in the tissues of your pancreas. Pancreas is an organ in your abdomen that lies horizontally behind the lower part of your stomach.

July 10, 2018

Pancreatic cancer begins in the tissues of your pancreas. Pancreas is an organ in your abdomen that lies horizontally behind the lower part of your stomach. It has cells with endocrine or hormonal and exocrine digestive functions. These cells Your pancreas releases hormones that help manage your blood sugar and enzymes that aid digestion respectively. Cancer cells can develop from both types of functional cells.
Pancreatic cancer is highly lethal because it grows and spreads rapidly and often is diagnosed in its late stages. Some screening steps might help detect a problem early for people with pancreatic cysts or a family history of pancreatic cancer.
squamous, pancreatic progenitor, aberrantly differentiated endocrine exocrine (ADEX), and immunogenic are subtypes of pancreatic cancer.
Symptoms and signs of pancreatic cancer in its late stage include weight loss and back pain. In some cases, painless jaundice may be a symptom of early pancreatic cancer that can be cured with surgery. Treatment may include surgery, chemotherapy, radiation therapy or a combination of these. Surgical removal of all cancer is the only curative treatment. This include removal of the entire pancreas, and a pancreatic transplant. However, few patients are eligible for a pancreatic transplant. Chemotherapy after surgery can lower the chances of recurrence of cancer. Chemotherapy for metastatic pancreatic cancer can extend life and improve the quality of life, but it rarely cures the patient.

Symptoms of Pancreatic cancer:

Usually pancreatic cancer does not cause symptoms until it has grown. Therefore it is very difficult to diagnose in early stage. Often it is diagnosed in advanced stages.
Jaundice without pain can be an early sign of pancreatic cancer in some cases. Many of the signs and symptoms of exocrine pancreatic cancer result from blockage of the duct that travels through the pancreas from the liver carrying bile to the intestine. These include:

  • nausea
  • vomiting
  • weight loss
  • itching skin
  • loss of appetite
  • new onset diabetes
  • blood clots
  • fatigue

Pale stools, back pain, abdominal pain, dark urine, abdominal bloating, diarrhea, and enlarged lymph nodes in the neck can be present as well.
Symptoms in women rarely differ from those in men. Once the tumor sheds cancer cells into the blood and lymph systems and metastasizes, additional symptoms usually arise, depending on the location of the metastasis. Liver, the lymph nodes, and the lining of the abdomen called the peritoneum are the most frequent sites of metastasis for pancreatic cancer.
If you experience unexplained weight loss or if you have persistent fatigue, abdominal pain, jaundice, or other signs and symptoms that bother you, visit your doctor immediately to rule out other conditions as many other health issues may have similar symptoms.
The signs and symptoms of endocrine pancreatic cancers will have a variety of different symptoms then exocrine cancer and are often related to the excess hormones. Such symptoms are related to the tumor produced by excess secretion of hormones and are as follows:

  • Insulinomas are insulin producing tumors that lower blood glucose levels resulting in weakness, confusion, coma, and even death.
  • Glucagonomas are glucagon producing tumors that can increase glucose levels and cause symptoms of diabetes such as thirst, increased urination, diarrhea and skin changes, especially a characteristic rash termed necrolytic migratory erythema.
  • Gastrinomas are gastrin producing tumors trigger the stomach to produce too much acid, which leads to ulcers, black tarry stools, and anemia.
  • Somatostatinomas are somatostatin producing tumors result in other hormones being overregulated and producing symptoms of diabetes, diarrhea, belly pain, jaundice, and possibly other problems.
  • VIPomas are tumors that produces a substance called vasoactive intestinal peptide (VIP) which may cause severe watery diarrhea and digestive problems along with high blood glucose levels.
  • PPomas are tumors that produces pancreatic polypeptide (PP) which affects both endocrine and exocrine functions, resulting in abdominal pain, enlarged livers, and watery diarrhea.
  • Carcinoid tumors are tumors that make serotonin or its precursor, 5-HTP, and may cause the carcinoid syndrome with symptoms of flushing of the skin, diarrhea, wheezing, and a rapid heart rate that occurs episodically. Eventually, a heart murmur, shortness of breath, and weakness develop due to damage to the heart valves.

Nonfunctioning neuroendocrine tumors don't make excess hormones but can grow large and spread out of the pancreas. Symptoms are similar to any of the endocrine pancreatic cancers described above.

Function of your Pancreas:

Your pancreas is an organ in the abdomen that sits in front of the spine above the level of the belly button and is about 6 inches (15 centimeters) long and looks something like a pear lying on its side.
It performs two main functions:

  • Endocrine function: It makes insulin, a hormone that regulates blood sugar levels.
  • Exocrine function: It produces the intestine digestive enzymes which help break down dietary proteins, fats, and carbohydrates.

These enzymes leave the pancreas via a system of tubes called ducts that connect the pancreas to the intestines where the enzymes mix with ingested food and help digestion by chopping proteins, fats, and carbohydrates into smaller parts so that they can be more easily absorbed by the body and used as building blocks for tissues and for energy.
The pancreas sits deep in the abdomen and is in close proximity to many important structures such as the small intestine or the duodenum and the bile ducts, as well as important blood vessels and nerves.

Causes of Pancreatic cancer:

Pancreatic cancer occurs when cells in your pancreas develop mutations in their DNA resulting in uncontrollable grow of abnormal cells. The normal cells would die and these cells continue living and accumulating which can form a tumor. Untreated pancreatic cancer spreads to nearby organs and blood vessels.

Types of pancreatic cancer:

There are two major categories of pancreatic cancer. These are

  • Cancers of the endocrine pancreas that is the part that makes insulin and other hormones are called islet cell or pancreatic neuroendocrine tumors or PNETs . Islet cell cancers are rare and typically grow slowly compared to exocrine pancreatic cancers. Islet cell tumors often release hormones into the bloodstream and are further characterized by the hormones they produce such as insulin, glucagon, gastrin, and other hormones.
  • Cancers of the exocrine pancreas that is the part that makes enzymes. Cancers of the exocrine pancreas develop from the cells that line the system of ducts that deliver enzymes to the small intestine and are commonly referred to as pancreatic adenocarcinomas. All most all pancreatic cancer begins in these cells.

Squamous cell pancreatic cancer is rare. Pancreatic adenocarcinomas are further classified as four subtypes after analysis of the genes. The subtypes include:

  • Squamous: These tumors occurs after TP53 and KDMA gene mutations.
  • Pancreatic progenitor: These tumors express genes involved in pancreatic development such as FOXA2/3, PDX1, and MNX1.
  • Aberrantly differentiated endocrine exocrine (ADEX): These tumors display the genes (KRAS) and exocrine (NR5A2 and RBPJL) plus endocrine (NEUROD1 and NKX2-2) differentiation.
  • Immunogenic: These tumors contain pathways that are involved in acquired immune suppression.

These new findings may help treating patient more specifically depending on their subtype and, hopefully, more effectively. For example, the immunogenic subtype could possibly respond to therapy where the immune system is designed to attack these types of cancer cells.
Pancreatic cancer should not be confused with pancreatitis which is just an inflammation of the pancreas and is mainly caused by alcohol abuse and /or gallstone formation. However, chronic pancreatitis is associated with pancreatic cancer.

Risk factors of Pancreatic cancer:

Most people who develop pancreatic cancer usually do not have any risk factors. However, the biggest risk factor is increasing age. Being over the age of 60 puts an individual at greater risk. There can be familial or hereditary genetic syndromes arising from genetic mutations which is very rare. If BRCA-2 and, to a lesser extent, BRCA-1 gene mutations run in families that can put an individuals at higher risk.
Additionally, certain behaviors or conditions are thought to slightly increase the risk of an individual for developing pancreatic cancer. These include:

  • Chronic inflammation of the pancreas called pancreatitis
  • Diabetes
  • Smoking
  • Obesity
  • fatty diet
  • sedentary lifestyle

Prior stomach surgery or certain chronic infections such as hepatitis B and H. pylori may moderately increases the risk of an individual. Certain drugs such as sitagliptin and metformin are associated with the development of pancreatic cancer. Some types of pancreatic cysts may put individuals at risk of developing pancreatic cancer.

Complications of Pancreatic cancer:

Complications of Pancreatic cancer include:

Weight loss:

A number of factors may cause weight loss in people with pancreatic cancer. These include:

  • The cancer itself may cause weight loss.
  • Nausea and vomiting caused by cancer treatments or a tumor pressing on your stomach may make it difficult to eat.
  • As your pancreas isn't producing enough digestive juices or enzymes, your body may have difficulty processing nutrients from food.

To improve your digestion, pancreatic enzyme supplements may be recommended. Try to maintain your weight by adding extra calories and making mealtime as pleasant and relaxed as possible.

Jaundice:

Pancreatic cancer that blocks the bile duct of liver can cause jaundice. Signs and symptoms include yellow skin and eyes, dark colored urine, and pale colored stools. Jaundice usually occurs without abdominal pain. A plastic or metal tube called stent can be placed inside the bile duct to hold it open. This is done with the help of a procedure called endoscopic retrograde cholangiopancreatography (ERCP). During ERCP an endoscope is passed down your throat, through your stomach and into the upper part of your small intestine. A dye is then injected into the pancreas and bile ducts through a small hollow tube called catheter that is passed through the endoscope. Finally, images are taken of the ducts and stent can be placed inside the bile duct.

Pain:

A growing tumor may press on nerves in your abdomen, causing pain that can become severe. Pain medications can help you feel more comfortable in this case.
Radiation therapy might help stop tumor growth temporarily to give you some relief.
In severe cases, alcohol can be injected into the nerves that control pain in your abdomen. This procedure stops the nerves from sending pain signals to your brain.
Bowel obstruction:
If the pancreatic cancer grows into or presses on the first part of the small intestine called duodenum, that can block the flow of digested food from your stomach into your intestines. In this case a tube or stent can be placed in your small intestine to hold it open. Surgery may be necessary to attach your stomach to a lower point in your intestines that isn't blocked by cancer.

Prevention of Pancreatic cancer:

Pancreatic cancer can be prevented if you:

Stop smoking:

Quit smoking if you smoke. Talk to your doctor about strategies to help you stop. He will be able to advise you regarding support groups, medications and nicotine replacement therapy. Don't start smoking if you don't.

Maintain a healthy weight:

Try to maintain a healthy weight. Aim for a slow and steady weight loss if you need to lose weight. Regular exercise with a diet rich in vegetables, fruit and whole grains with smaller portions to help you lose weight.

Choose a healthy diet:

A diet full of colorful fruits and vegetables and whole grains may help reduce your risk of cancer. If you have a family history of pancreatic cancer, take advise from a genetic counselor. He or she can review your family health history with you and determine whether you might benefit from a genetic test to understand your risk of pancreatic cancer or other cancers.