What is pancreatic cancer?
Pancreatic cancer begins in the tissue of the pancreas – an organ in your abdomen located behind the lower part of your stomach. The pancreas secretes enzymes that aid digestion and produce hormones that aid in managing blood sugar.
The pancreas is a 6-inch-long organ located behind the stomach in the back of the abdomen, near the gallbladder. It covers glands that create pancreatic juices, hormones, and insulin. Cancer can affect both the endocrine and exocrine glands of the pancreas. The exocrine glands produce juices or enzymes that enter the intestines and help digest fats, proteins, and carbohydrates. They make up most of the pancreas.
The endocrine glands are small collections of cells known as islets of Langerhans. The announcement the hormones insulin and glucagon into the bloodstream. There they control blood sugar levels. When they don’t work properly, the result is usually diabetes. The type of cancer and the prognosis for each depends on the function that cancer affects.
Types of pancreatic cancer
There are two different types of pancreatic cancer, depending on whether it affects exocrine or endocrine functions. They have different risk factors, causes, symptoms, diagnostic tests, treatments, and outlooks.
Exocrine pancreatic cancer
Tumors that affect exocrine functions are the most common type. They can be malignant or benign. Benign tumors or cysts are called cystadenomas. Most pancreatic tumors are malignant or cancerous. Different types of pancreatic cancers can affect exocrine functions.
The types of tumor include:
- Adenocarcinomas, which usually begin in the cells of the glands of the ducts of the pancreas
- Acinar cell carcinoma, which begins in the cells of the pancreatic enzyme
- Ampullary cancer, which begins where the bile duct and pancreatic duct meet the duodenum of the small intestine
- Adenosquamous carcinomas
- Squamous cell carcinomas
- Giant cell carcinomas
- Endocrine pancreatic cancer
Tumors that affect the endocrine functions of the pancreas are called neuroendocrine or islet cell tumors. They are quite rare. The name comes from the type of hormone-producing cell where cancer begins.
- Insulinomas (insulin)
- Glucagonomas (glucagon)
- Gastrinomas (gastrin)
- Somatostatinomas (somatostatin)
- VIPomas (vasoactive intestinal peptide or VIP)
Working islet cell tumors continue to produce hormones. The ones that don’t work don’t. Most of these tumors are benign, but the ones that don’t work are more likely to be malignant islet cell carcinomas.
Symptoms of pancreatic cancer
Because the pancreas is deep in the abdomen in front of the spine, pancreatic cancer often grows quietly for months before being discovered. The early cancer symptoms and/or early signs may be absent or quite subtle. The easiest to identify symptoms develop once the tumor grows enough to press on other nearby structures, such as the nerves (which causes widespread pain and/or back pain), the intestines (which affects appetite and causes nausea together with weight loss) or bile ducts (which causes jaundice or yellowing of the skin and can cause loss of appetite and itching). Symptoms in women rarely differ from those in men.
Once the tumor sheds cancer cells into the blood and lymphatic systems and metastasizes, extra symptoms usually arise, contingent on the location of the metastasis. Common sites of metastasis for pancreatic cancer include the liver, lymph nodes, and the lining of the abdomen (called the peritoneum; ascites fluid can accumulate in metastatic pancreatic cancer). Unfortunately, most pancreatic cancers are found after cancer has full-grown or advanced beyond the pancreas or has metastasized to other places.
In general, the signs and symptoms of pancreatic cancer can be caused by exocrine or endocrine cancer cells. Many of the signs and symptoms of exocrine pancreatic cancer are due to a blockage of the duct that travels through the pancreas from the liver that carries bile to the intestine. Symptoms of exocrine pancreatic cancer include
- Dark urine
- Skin itch
- Light-coloured stools
- Pain in the abdomen or back
- Lack of appetite and weight loss
- Digestive difficulties (pale and/or greasy stools, nausea and vomiting)
- Blood clots, and
- Enlarged gallbladder
The signs and symptoms of endocrine pancreatic cancers are often related to the excess hormones they produce, and so to a variety of diverse symptoms. These symptoms are related to hormones and are as follows:
- Insulinomas: Insulin-producing tumors that lower blood glucose (sugar) levels can cause low blood sugar levels that lead to weakness, confusion, coma, and even death.
- Glucagonomas: Glucagon-producing tumors can increase glucose levels and cause symptoms of diabetes (thirst, increased urination, diarrhea, and skin changes, especially a characteristic rash called necrolytic erythema migrans).
- Gastrinomas: Gastrin-producing tumors cause the stomach to produce too much acid, leading to ulcers, black tar stools, and anemia.
- Somatostatinomas: Somatostatin-producing tumors cause other hormones to develop over-regulated, causing symptoms of diabetes, diarrhea, stomach pain, jaundice, and possibly other problems.
- VIPomas: These tumors produce a material called a vasoactive intestinal peptide (VIP) that can cause severe watery diarrhea and digestive difficulties along with high blood glucose levels.
- PPomas: These tumors produce pancreatic polypeptide (PP) that affects endocrine and exocrine functions, leading to abdominal pain, liver enlargement, and watery diarrhea.
- Carcinoid tumors: These tumors produce serotonin or its precursor, 5-HTP, and can cause carcinoid syndrome with symptoms of red skin, diarrhea, wheezing, and a rapid heart rate that occurs on an episodic basis; Eventually, a heart murmur, shortness of breath, and weakness develop due to damage to the heart valves.
Non-functional neuroendocrine tumors do not overproduce hormones, but they can grow and spread outside of the pancreas. So the symptoms can be similar to any of the endocrine pancreatic cancers described above.
Causes of pancreatic cancer
The cause of pancreatic cancer is unknown. This type of cancer occurs when abnormal cells begin to grow inside the pancreas and form tumors. Usually, healthy cells grow and die in reasonable numbers. In the case of cancer, there is a greater amount of abnormal cell production and these cells eventually take over healthy cells.
While doctors and researchers don’t know what causes cell changes, they do know about some common factors that can increase a person’s risk of developing this type of cancer. The two most important risk factors are inherited genetic mutations and acquired genetic mutations. Genes control the way cells work, so changes in those genes can lead to cancer.
A pancreatic tumor can only be seen on an imaging study, such as computed tomography (CT) scan, magnetic resonance imaging (MRI), or endoscopic ultrasound (EUS). The doctor then takes a sample of the tumor tissue to determine the exact diagnosis.
Why is pancreatic cancer hard to find?
The pancreas is situated deep in the abdomen, so doctors usually cannot see or feel the tumor during a physical exam. Also, symptoms of pancreatic cancer are not always obvious and usually develop over time. Physicians can use various tests to make a diagnosis. But there is no normal test to diagnose pancreatic cancer. This makes the diagnosis even more complicated.
Treatment of pancreatic cancer
The best treatment for pancreatic cancer depends on how far it has spread or its stage. The stages of pancreatic cancer are easy to understand. The difficult thing is trying to stage pancreatic cancer without resorting to major surgery. In practice, doctors choose treatments for pancreatic cancer based on imaging studies, surgical findings, and a person’s general state of well-being.
Stages of pancreatic cancer
The stage is a term used in cancer treatment to describe how far cancer has spread. The stages of pancreatic cancer are used to guide treatment and classify patients for clinical trials. The stages of pancreatic cancer are:
Stage 0: No propagation: Pancreatic cancer is limited to the upper layers of cells in the ducts of the pancreas. Pancreatic cancer is not visible on imaging tests or even with the naked eye.
Stage I: Local growth: Pancreatic cancer is confined to the pancreas, but has grown to less than 2 centimetres wide (stage IA) or more than 2 but not more than 4 centimetres (stage IB).
Stage II: Local spread: Pancreatic cancer is larger than 4 centimetres and is limited to the pancreas or there is a local spread where cancer has grown outside the pancreas or has spread to nearby lymph nodes. It has not spread to distant sites.
Stage III: Wider spread: The tumor may have spread to nearby major blood vessels or nerves, but has not metastasized to distant sites.
Stage IV: Confirmed spread: Pancreatic cancer has spread to distant organs.
Determining the stage of pancreatic cancer is often difficult. Imaging tests, such as CT scan and ultrasound, provide some information, but to find out exactly how far pancreatic cancer has spread, surgery is usually required. Since surgery has risks, doctors first determine whether pancreatic cancer appears to be surgically removable (resectable). Pancreatic cancer is described below as follows:
- Resectable: On imaging tests, pancreatic cancer hasn’t spread (or at least not very far), and one surgeon thinks everything could be removable. About 10% of pancreatic cancers are considered resectable when they are first diagnosed.
- Locally advanced (unresectable): Pancreatic cancer has become important blood vessels on imaging tests, so the tumor cannot be safely removed by surgery.
- Metastatic: Pancreatic cancer has clearly spread to other organs, so surgery cannot remove cancer.
Factors that can surge your risk of pancreatic cancer include:
- Of smoking
- Chronic inflammation of the pancreas (pancreatitis)
- Family history of genetic syndromes that can increase the risk of cancer, including a BRCA2 gene mutation, Lynch syndrome, and familial atypical molar malignant melanoma syndrome (FAMMM)
- Family history of pancreatic cancer.
- Elder age, as most people are diagnosed after age 65
A large study presented that the combination of smoking, long-term diabetes, and poor diet increases the risk of pancreatic cancer outside the risk of any of these factors alone.
As pancreatic cancer developments, it can cause complications such as:
- Weightloss: Several factors can cause weight loss in people with pancreatic cancer. Weight loss can occur because cancer consumes the body’s energy. Nausea and vomiting caused by cancer treatments or a tumor pressing on the stomach can make eating difficult. Or your body may have a hard time processing the nutrients in food because your pancreas doesn’t make enough digestive juices.
- Jaundice: Pancreatic cancer that blocks the bile duct of the liver can cause jaundice. Signs contain yellow skin and eyes, dark-coloured urine, and pale-coloured stools. Jaundice generally occurs without abdominal pain.
Your doctor may recommend that a plastic or metal tube (stent) be placed inside the bile duct to keep it open. This is complete with the help of a process called endoscopic retrograde cholangiopancreatography (ERCP). During ERCP, an endoscope is passed down the throat, through the stomach, and into the upper part of the small intestine. A dye is then injected into the pancreatic and bile ducts finished by a small hollow tube (catheter) that is passed through the endoscope. Finally, pictures of the ducts are taken.
- Pain: A growing tumor can press on nerves in the abdomen and cause pain that can become severe. Pain relievers can help you feel more comfortable. Treatments, such as radiation and chemotherapy, can help slow tumor growth and relieve pain.
In severe cases, your doctor may recommend a procedure to inject alcohol into the pain-controlling nerves in your abdomen (celiac plexus block). This procedure prevents nerves from sending pain signals to your brain.
- Intestinal obstruction: Pancreatic cancer that grows or presses on the first part of the small intestine (duodenum) can block the flow of digested food from the stomach to the intestines.
Your doctor may recommend that a tube (stent) be placed in your small intestine to keep it open. In some situations, it may be helpful to have surgery to place a temporary feeding tube or attach the stomach to a lower point in the intestines that are not blocked by cancer.
You can decrease your risk of pancreatic cancer by:
- Stop smoking: If you smoke, try to stop. Talk to your doctor about strategies to help you quit smoking, including support groups, medications, and nicotine replacement therapy. If you don’t smoke, don’t start.
- Keep a healthy weight: If you are at a healthy weight, work to uphold it. If you need to lose weight, try to lose weight slowly and steadily – 1 to 2 pounds (0.5 to 1 kilogram) a week. Syndicate daily exercise with a diet rich in vegetables, fruits, and whole grains with lesser portions to help you lose weight.
- Choose a healthy diet: A diet rich in colourful fruits and vegetables and whole grains can help reduce your risk of cancer.
Reflect on meeting with a genetic counsellor if you have a family history of pancreatic cancer. He or she can appraisal your family health history with you and determine if you could benefit from genetic testing to understand your risk for pancreatic or other cancers.