Pancreatic Cancer
Pancreatic cancer arises when cells in the pancreas, a glandular organ behind the stomach, begin to multiply out of control and form a mass. These cancerous cells have the ability to invade other parts of the body. There are a number of types of pancreatic cancer. Pancreatic cancer is a disease in which malignant (cancerous) cells form in the tissues of the pancreas. The pancreas is a gland located behind the stomach and in front of the spine. The pancreas produces digestive juices and hormones that regulate blood sugar. Cells called exocrine pancreas cells produce the digestive juices, while cells called endocrine pancreas cells produce the hormones. The majority of pancreatic cancers start in the exocrine cells. This cancer may metastasize or spread top surrounding organs and lymph nodes such as lungs and liver.
Types of Pancreatic Cancer
Pancreatic cancers are grouped into two main types:
Endocrine tumors
Tumors of the endocrine pancreas are uncommon, making up less than 4% of all pancreatic cancers. As a group, they are sometimes known as pancreatic neuroendocrine tumors (NETs) or islet cell tumors.
Pancreatic NETs can be benign or malignant (cancer). Benign and malignant tumors can look alike under a microscope, so it isn’t always clear whether or not a pancreatic NET is cancer. Sometimes the diagnosis only becomes clear when the tumor spreads outside of the pancreas.
There are many types of pancreatic NETs
Functioning tumors: About half of pancreatic NETs make hormones that are released into the blood and cause symptoms. These are called functioning tumors. Each one is named for the type of hormone-making cell it starts in.
Pancreatic NETs can be benign or malignant (cancer). Benign and malignant tumors can look alike under a microscope, so it isn’t always clear whether or not a pancreatic NET is cancer. Sometimes the diagnosis only becomes clear when the tumor spreads outside of the pancreas.
There are many types of pancreatic NETs
Functioning tumors: About half of pancreatic NETs make hormones that are released into the blood and cause symptoms. These are called functioning tumors. Each one is named for the type of hormone-making cell it starts in.
- Gastrinomas come from cells that make gastrin. About half of gastrinomas are cancers.
- Insulinomas come from cells that make insulin. Most insulinomas are benign (not cancers).
- Glucagonomas come from cells that make glucagon. Most glucagonomas are cancers.
- Somatostatinomas come from cells that make somatostatin. Most somatostatinomas are cancers.
- VIPomas come from cells that make vasoactive intestinal peptide (VIP). Most VIPomas are cancers.
- PPomas come from cells that make pancreatic polypeptide. Most PPomas are cancers.
The most common types of functioning NETs are gastrinomas and insulinomas. The other types occur very rarely
. Exocrine tumors
Exocrine tumors are by far the most common type of pancreas cancer. When someone says that they have pancreatic cancer, they usually mean an exocrine pancreatic cancer.
Pancreatic adenocarcinoma: An adenocarcinoma is a cancer that starts in gland cells. About 95% of cancers of the exocrine pancreas are adenocarcinomas. These cancers usually begin in the ducts of the pancreas. But sometimes they develop from the cells that make the pancreatic enzymes, in which case they are called acinar cell carcinomas.
Less common types of cancers: Other cancers of the exocrine pancreas include adenosquamous carcinomas, squamous cell carcinomas, signet ring cell carcinomas, undifferentiated carcinomas, and undifferentiated carcinomas with giant cells. These types are distinguished from one another based on how they look under the microscope.
Solid pseudopapillary neoplasms (SPNs): These are rare, slow-growing tumors that almost always occur in young women. Even though these tumors tend to grow slowly, they can sometimes spread to other parts of the body, so they are best treated with surgery. The outlook for people with these tumors is usually very good.
Ampullary cancer (carcinoma of the ampulla of Vater): This cancer starts in the ampulla of Vater, which is where the bile duct and pancreatic duct come together and empty into the small intestine. Ampullary cancers aren’t technically pancreatic cancers, but they are included in this document because their treatments are very similar.
Ampullary cancers often block the bile duct while they are still small and have not spread far. This blockage causes bile to build up in the body, which leads to yellowing of the skin and eyes (jaundice) and can turn urine dark. Because of this, these cancers are usually found at an earlier stage than most pancreatic cancers, and they usually have a better prognosis (outlook) than typical pancreatic cancers
Pancreatic adenocarcinoma: An adenocarcinoma is a cancer that starts in gland cells. About 95% of cancers of the exocrine pancreas are adenocarcinomas. These cancers usually begin in the ducts of the pancreas. But sometimes they develop from the cells that make the pancreatic enzymes, in which case they are called acinar cell carcinomas.
Less common types of cancers: Other cancers of the exocrine pancreas include adenosquamous carcinomas, squamous cell carcinomas, signet ring cell carcinomas, undifferentiated carcinomas, and undifferentiated carcinomas with giant cells. These types are distinguished from one another based on how they look under the microscope.
Solid pseudopapillary neoplasms (SPNs): These are rare, slow-growing tumors that almost always occur in young women. Even though these tumors tend to grow slowly, they can sometimes spread to other parts of the body, so they are best treated with surgery. The outlook for people with these tumors is usually very good.
Ampullary cancer (carcinoma of the ampulla of Vater): This cancer starts in the ampulla of Vater, which is where the bile duct and pancreatic duct come together and empty into the small intestine. Ampullary cancers aren’t technically pancreatic cancers, but they are included in this document because their treatments are very similar.
Ampullary cancers often block the bile duct while they are still small and have not spread far. This blockage causes bile to build up in the body, which leads to yellowing of the skin and eyes (jaundice) and can turn urine dark. Because of this, these cancers are usually found at an earlier stage than most pancreatic cancers, and they usually have a better prognosis (outlook) than typical pancreatic cancers
Symtons of Pancreatic cancer
the three most common symptoms are:
- pain in the stomach or back
- jaundice
- weight loss
Other possible symptoms of pancreatic cancer include:
- itching (if you have jaundice)
- nausea and vomiting
- bowel changes
- fever and shivering
- indigestion
- blood clots
Causes of Pancreatic Cancer
Age
- Smoking
- Diabities
Chronic pancreatitis and hereditary pancreatitis
Helicobacter pylori infection
There are also a number of other factors that have been associated with an increased risk of pancreatic cancer. These are:
- long-term hepatitis
- tooth or gum disease
- heavy alcohol use
- a previous history of certain types of cancer
- previously having radiotherapy
- diet, weight and level of physical activity
Stages of Pancreatic Cancer
here are 4 stages in this system – stage 1 to 4.
Stage 1
Stage 1 means the cancer is completely inside the pancreas and has not spread to the lymph nodes. It is divided into
Stage 1A means the cancer is completely inside the pancreas and is smaller than 2 cm. There is no cancer in the lymph nodes or other areas of the body. In TNM staging, this is the same as T1, N0, M0.
Stage 1B means the cancer is completely inside the pancreas but is bigger than 2cm. There is no cancer in the lymph nodes or other areas of the body. In TNM staging, this is the same as T2, N0, M0.
Stage 2
Stage 2 is divided into
Stage 2A means the cancer has started to grow into nearby tissues around the pancreas. It may be in the duodenum or the bile duct. But there is no cancer in the nearby large blood vessels or lymph nodes. This means that, although the cancer has been growing locally, there is a chance that it may not have spread through the blood or lymph systems. In TNM staging, this is the same as T3, N0, M0.
Stage 2B means the cancer can be any size and may have grown into the tissues surrounding the pancreas. Cancer is also found in the nearby lymph nodes, but not the large blood vessels. In TNM staging, this is the same as T1, 2 or 3, N1, M0.
Stage 3
The cancer is growing outside the pancreas, into the nearby large blood vessels. It may or may not have spread into the lymph nodes. It has not spread to other areas of the body. Your doctor may call this locally advanced cancer. In TNM staging, this is the same as T4, Any N, M0.
Stage 4
The cancer has spread to other areas of the body such as the liver or lungs. Your doctor may call this advanced cancer. In TNM staging, this is the same as Any T, Any N, M1.
Diagnosis of Pancreatic Cancer
The diagnosis of pancreatic cancer involves performing a number of imaging studies that include –
Computerised tomography (CT) scan
A computerised tomography (CT) scan produces a detailed image of the inside of your body using a series of X-rayimages
Magnetic resonance imaging (MRI) scan
A magnetic resonance imaging (MRI) scan also produces an image of the inside of your body, but it uses strong magnetic and radio waves instead of X-rays.
Positron emission tomography (PET) scan
A positron emission tomography (PET) scan can help to show where the cancer is and whether it has spread to other parts of the body
Endoluminal ultrasonography (EUS)
If a small shadow is seen on a CT or MRI scan but it’s not obvious what it is, another test called endoluminal ultrasonography (EUS) can be carried out.
Endoscopic retrograde cholangiopancreatography (ERCP)
Endoscopic retrograde cholangiopancreatography (ERCP) is a procedure used to insert a plastic tube or stent into the bile duct if someone has jaundice.
During ERCP, an endoscope is passed through your mouth and guided towards your stomach. The endoscope can then be used to inject a special dye into your bile and pancreatic ducts.
After the dye has been injected, an X-ray will be taken. The dye will show up on the X-ray and will highlight any tumour that’s blocking the bile and pancreatic ducts.
Laparoscopy
A laparoscopy is a surgical procedure that allows the surgeon to access the inside of your abdomen and pelvis.
During the procedure, a small incision will be made in your abdomen, and a laparoscope (a thin, flexible microscope) will be inserted.
Biopsy
A biopsy involves taking a sample from a suspected tumour, which can then be tested to see if it’s cancerous (malignant) or non-cancerous (benign).
A biopsy can be carried out during an EUS, ERCP or laparoscopy using a small instrument attached to the endoscope to collect a number of cells.
Ultrasound scan
An ultrasound scan is a painless procedure that uses high-frequency sound waves to produce an image of the inside of your body.
Treatment of Pancreatic Cancer
Treatment for pancreatic cancer depends on the type, location and stage of your cancer (how far it’s spread).
Your age, general health and personal preferences will also be taken into consideration when deciding on your treatment plan.
The first aim will be to completely remove the tumour and any other cancerous cells in your body.
There are 2 general types of surgery used for pancreatic cancer:
- Potentially curative surgery is used when the results of exams and tests suggest that it is possible to remove all the cancer.
- Palliative surgery may be done if imaging tests show that the tumor is too widespread to be removed completely. This surgery is done to relieve symptoms or to prevent certain complications like a blocked bile duct or intestine, but it is not meant to try to cure the cancer.
Palliative Surgery
Palliative surgery is meant to treat the symptoms of the cancer and prevent problems that may potentially arise as a result of the cancer.
One problem palliative surgery may be able to treat is blockage of the bile duct. Having a blocked bile duct can not only be painful, it can also interfere with digestion and cause jaundice.
The two main options to relieve blockage are stent placement and bypass surgery.
Endoscopic Stent Placement
Stent placement is the most common procedure used to relieve blockage in the bile ducts. For this less invasive procedure, the gastroenterologist uses an endoscope to place small plastic or metal stents into the duct to relieve blockage. Larger stents can be used to relieve intestinal blockage.
Operative Biliary and Intestinal Bypass
Instead of bile flowing from the common bile duct through the pancreas, bypass surgery redirects the flow of bile from the common bile duct into the small intestine. Additionally, if the duodenum or stomach is blocked by the tumor, a loop of intestine can be sewn to the stomach further up to allow food to be more easily digested.
Medical Therapy
Medical therapy uses drugs to destroy cancer cells.
Chemotherapy
For patients with early pancreatic cancer, chemotherapy is generally given after surgery (called adjuvant therapy), though in some cases, it may be given before (called neoadjuvant therapy). For patients with advanced disease, chemotherapy may be given alone or in combination with other treatments
Targeted Therapy
Targeted therapy targets specific genes in cancer cells, causing less damage to healthy cells. Targeted therapy drugs for pancreatic cancer help stop the growth and spread of the cancer
Radiation Therapy
Radiation therapy uses high-energy rays (such as x-rays) to destroy cancer cells. It can be given before surgery (neoadjuvant therapy) or after surgery (adjuvant therapy). It can also be given in combination with other types of treatment.
Radiation therapy can be combined with chemotherapy to treat pancreatic cancer patients whose cancers are too widespread to be treated with surgery
Curative Surgeries for pancreatic cancer
Most curative surgery is designed to treat cancers at the head of the pancreas. Because these cancers are near the bile duct, some of them cause jaundice and are found early enough to be removed. Surgeries for other parts of the pancreas are typically only done when complete removal of the cancer will be possible.
There are several procedures used to remove tumors of the pancreas:
Pancreaticoduodenectomy (Whipple procedure)
This is the most common operation to remove a cancer of the exocrine pancreas. It involves removing the head of the pancreas and sometimes the body of the pancreas as well. At times, part of the stomach, small intestine, and lymph nodes near the pancreas are also removed. The gallbladder and part of the common bile duct are removed, and the remaining bile duct is attached to the small intestine so that bile from the liver can continue to enter the small intestine. Removal of tissue called the mesopancreas (RMP) may also be combined with the Whipple procedure. This tissue which contains cancer cells or cells that secrete compounds that may help the cancer grow, prevent it from dying or inhibit some chemotherapy.
Distal pancreatectomy
This operation removes only the tail of the pancreas or the tail and a portion of the body of the pancreas. The spleen is usually removed as well. This operation is used more often with islet cell tumor and less often, adenocarcinoma of the pancreas found in the tail and body of the pancreas. Another name for this surgery is radical antegrade pancreatosplenectomy or RAMPS procedure. This operation may sometimes be completed laparoscopically.
Total pancreatectomy
This operation was once used for tumors in the body or head of the pancreas. It removes the entire pancreas and often the spleen. It is now seldom used to treat exocrine cancers of the pancreas because there does not seem to be any advantage to removing the whole pancreas. It is possible to live without a pancreas, but when the entire pancreas is removed, people are left without any islet cells, the cells that make insulin. These people develop diabetes, which can be hard to manage because they become totally dependent on insulin. Total pancreatectomy is now done primarily for IPMN when the entire duct is at risk. If this is the case, the patient sees an endocrinologist pre-surgery to learn how to manage their diabetes. It is never done for adenocarcinoma unless there are unusual compelling reasons
Ablative Techniques for pancreatic cancer
Ablation refers to treatments that destroy tumors, usually with extreme heat or cold. This type of treatment typically does not require a hospital stay. There are different kinds of ablative treatments:
Radiofrequency ablation (RFA): This procedure uses high-energy radio waves for treatment. The doctor inserts a thin, needle-like probe into the tumor. A high-frequency current is then passed through the tip of the probe, which heats the tumor and destroys the cancer cells. This treatment is used mainly for small tumors.
Microwave thermotherapy: This procedure is similar to RFA, except microwaves are used to heat and destroy the abnormal tissue.
Cryosurgery (cryoablation): This procedure destroys a tumor by freezing it using a thin metal probe. The probe is guided into the tumor, and very cold gasses are passed through the probe to freeze the tumor, killing the cancer cells. This method can be used to treat larger tumors than the other ablation techniques, but it sometimes requires general anesthesia (where you are deeply asleep and not able to feel pain).
