Pancreatic cancer happens when uncontrolled cell growth begins in a part of the pancreas. Tumors develop, and these interfere with the way the pancreas works.
Pancreatic cancer often shows no symptoms until the later stages. For this reason, it can be difficult to manage.
According to the American Cancer Society, around 3 percent of all cancers in the United States are pancreatic cancers. In 2018, they expect around 55,440 people to receive a diagnosis of pancreatic cancer.
The pancreas is a 6-inch long organ located behind the stomach in the back of the abdomen, near the gall bladder.
It contains glands that create pancreatic juices, hormones, and insulin.
Cancer can affect either the endocrine or the exocrine glands in the pancreas.
The exocrine glands produce juices, or enzymes, that enter the intestines and help digest fat, proteins, and carbohydrates. These make up most of the pancreas.
The endocrine glands are small clusters of cells known as the islets of Langerhans. They release the hormones insulin and glucagon into the bloodstream. There, they manage blood sugar levels. When they are not working properly, the result is often diabetes.
The type of cancer and the outlook for each depends on which function the cancer affects.
There are two different types of pancreatic cancer, depending on whether it affects the exocrine or endocrine functions. They have different risk factors, causes, symptoms, diagnostic tests, treatments, and outlook.
Exocrine pancreatic cancer
Tumors that affect the exocrine functions are the most common type.
They can be malignant or benign. Benign tumors or cysts are are called cystadenomas. Most pancreatic tumors are malignant, or cancerous.
Different types of pancreatic cancers can affect the exocrine functions.
Types of tumor include:
- adenocarcinomas, which typically start in gland cells in the ducts of the pancreas
- acinar cell carcinoma, which starts in the pancreatic enzyme cells
- ampullary cancer, which starts 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. These are fairly uncommon.
The name comes from the type of hormone-producing cell where the cancer starts.
- insulinomas (insulin)
- glucagonomas (glucagon)
- gastrinomas (gastrin)
- somatostatinomas (somatostatin)
- VIPomas (vasoactive intestinal peptide or VIP)
Functioning islet cell tumors continue to make hormones. Non-functioning ones do not. Most of these tumors are benign, but non-functioning tumors are more likely to be malignant, islet-cell carcinomas.
Scientists do not know exactly why uncontrolled cell growth happens in the pancreas, but they have identified some possible risk factors.
Damage or changes in a person's DNA can lead to damage in the genes that control cell division.
Hereditary genetic changes pass down through a family. There is evidence that pancreatic cancer can run in families.
Other genetic changes happen because of exposure to an environmental trigger, for example, tobacco.
A person with certain genetic syndromes is more likely to develop pancreatic cancer.
- hereditary breast and ovarian cancer syndrome
- non-polyposis colorectal cancer (Lynch syndrome)
Pancreatic cancers affect men than often than women.
This year, the American Cancer Society expect that 29,200 men and 26,240 women will receive a diagnosis of pancreatic cancer.
Substances that may increase the risk of pancreatic cancer include certain:
- chemicals used in metal refining
When the body comes into contact with a carcinogen, free radicals form. These damage cells and affect their ability to function normally. The result can be cancerous growths.
Other medical factors
Age is an important risk factor, especially after the age of 60 years.
Scientists have also found a link between cancer of the pancreas and several other diseases.
- cirrhosis or scarring of the liver
- infection of the stomach with the ulcer-causing bacteria, Helicobacter pylori (H. pylori)
- diabetes mellitus
- chronic pancreatitis, or inflammation of the pancreas
- gingivitis or periodontal disease
Some lifestyle factors may increase the risk:
- smoking cigarettes or exposure to tobacco smoke
- excess weight and a lack of exercise
- a diet that is high in red meat and fat and low in fruits and vegetables
- long-term, heavy consumption of alcohol, which can lead to chronic pancreatitis, a risk factor for pancreatic cancer
Pancreatic cancer is often called a "silent" disease, because symptoms do not show until the later stages.
Tumors of the pancreas cancers are usually too small to cause symptoms, and later symptoms are often non-specific.
However, when the cancer grows, there may be:
- pain in the upper abdomen as the tumor pushes against nerves
- jaundice, when problems with the bile duct and liver lead to a painless yellowing of the skin and eyes and darkening of the urine.
- loss of appetite, nausea, and vomiting
- significant weight loss and weakness
- pale or grey fatty stool
However, a number of other diseases can cause the same symptoms, so a doctor can often not diagnose pancreatic cancer until the later stages.
Other possible signs and symptoms include:
- Trousseau's sign, when spontaneous blood clots form in the portal blood vessels, deep veins of the arms and legs, or other superficial veins
- clinical depression, which people sometimes report before a diagnosis
Islet cell or neuroendocrine cancers of the pancreas may cause the pancreas to produce too much insulin or hormones.
The person may experience:
- weakness or dizziness
- muscle spasms
Pancreatic cancer appears differently, depending on which part of the pancreas the tumor is in, whether the "head" or the "tail."
Tumors at the tail end are more likely to result in pain and weight loss. At the other end, head tumors cause fatty stools, weight loss, and jaundice.
If the cancer spreads, or metastasizes, new symptoms can occur in the affected area and the rest of the body.
Symptoms of pancreatic cancer often do not appear until the later stages. If you experience jaundice or any other unusual symptoms, you should see a doctor.
If someone in the family has already had pancreatic cancer, or if you have any of the risk factors and are concerned about the possibility of developing it, you should also speak to a doctor. They may suggest screening.
A doctor will ask about symptoms, take a family and medical history, and carry out a physical examination. They will probably also recommend some tests.
The physician will pay special attention to common symptoms such as:
- abdominal or back pain
- weight loss
- poor appetite
- digestive problems
- gallbladder enlargement
- blood clots, deep venous thrombosis (DVT), or pulmonary embolism
- fatty tissue abnormalities
- swelling of lymph nodes
- steatorrhea, or fatty stools
Atypical diabetes mellitus, Trousseau's sign, and recent pancreatitis may also be indications that pancreatic cancer is present.
Possible tests include:
- blood tests
- urine tests
- stool tests
Blood tests can detect a chemical that pancreatic cancer cells release into the blood. Liver function tests check for bile duct blockage.
The doctor may request imaging tests to detect if a tumor is present, and, if so, to and see how far the cancer has spread.
Common imaging tests include:
- ultrasound or endoscopic ultrasound
- CT, MRI, or PET scans
- X-rays, possibly with a barium meal
- an angiogram
This can confirm a diagnosis. The doctor removes a small sample of tissue for examination under the microscope.
Next, the doctor will assess the stage of the cancer, or how far the cancer has spread, to determine which treatment options are suitable.
The stage depends on:
- the size and direct extent of the primary tumor
- how far the cancer has spread to nearby lymph nodes
- whether the cancer has metastasized, or spread, to other organs in the body
The stages range from stage 0 to stage IV.
Stage 0: There are cancerous cells in the top layers of pancreatic duct cells. They have not invaded deeper tissues or spread outside of the pancreas.
Stage IV: The cancer that has spread to distant sites throughout the body.
At stage 0, effective treatment is possible. At stage IV, tumors have spread to distant organs. A doctor would only recommend surgery to relieve pain or unblock ducts.
Cancer treatment depends on a variety of factors:
- the type of cancer
- the stage of the cancer
- the person's age, health status, and other characteristics
- the individual's personal choices
Surgery, radiation, and chemotherapy are the most common treatment options.
The aim of treatment is to:
- remove the cancer
- relieve painful symptoms
Surgery can remove all or part of the pancreas.
If the cancerous cells are still in one area, as in the early stages, it is possible to remove all of the cancer. The further the cells spread, the more difficult this becomes.
This is why an early diagnosis is best for any type of cancer.
The three main surgical procedures that can help people with pancreatic cancer are:
Whipple procedure: This most common if cancer affects the head of the pancreas. The surgeon removes the pancreas head, and sometimes the whole pancreas, along with a portion of the stomach, duodenum, lymph nodes, and other tissue. This is a complex and risky procedure. Complications include leaking, infections, bleeding, and stomach problems.
Distal pancreatectomy: The surgeon removes the pancreas tail, and sometimes other parts of the pancreas, along with the spleen. Doctor usually recommend this procedure to treat islet cell or neuroendocrine tumors.
Total pancreatectomy: The surgeon removes the entire pancreas and spleen. It is possible to live without a pancreas, but diabetes may result because the body no longer produces insulin cells.
Palliative surgery is an option when it is not possible to remove the cancer in the pancreas.
If there is a blockage in the common bile duct or the duodenum, the surgeon can create a bypass so that bile can continue to flow from the liver. This can minimize pain and digestive problems.
Another way to relieve a bile duct blockage is by inserting a small stent in the duct to keep it open. This is a less invasive procedure using an endoscope.
Chemotherapy is a form of medication that interferes with the cell division process that causes cancer cells to grow. As the medication travels through the body, it can treat cancer that has spread.
Treatment occurs in cycles, so that the body has time to heal between doses.
Side effects include:
- hair loss
- nausea and vomiting
Combination therapies may involve different types of chemotherapy or chemotherapy with other treatment options.
The chemotherapy drug that doctors most commonly use to treat pancreatic cancer is gemcitabine (Gemzar). The person usually receives it intravenously on a weekly basis.
Adjuvant therapy is chemotherapy that comes after surgery. It aims to kill any cancer cells that remain.
Palliative chemotherapy aims to improve an individual's quality of life in the later stages of cancer.
Biologics are newer drugs that target specific parts of cancer cells. As they do not affect the whole body, they often have fewer side effects.
One such drug, erlotinib (Tarceva), has helped some people with advanced pancreatic cancer. The person takes it by mouth, as a pill.
Radiation therapy destroys cancer by focusing high-energy rays on the cancer cells.
As a standalone treatment, it can shrink a tumor or destroy cancer cells. Doctors may also combine it with other cancer treatments, such as chemotherapy and surgery.
A person will normally receive radiation therapy for pancreatic cancer 5 days a week for 5 to 6 weeks.
As a palliative treatment, radiation therapy can relieve pain or digestive problems when there is a blockage in the common bile duct or duodenum.
The side effects include:
- mild skin changes resembling sunburn or suntan
- nausea, vomiting, and diarrhea
- loss of appetite
- weight loss
Most side effects subside a few weeks after completing treatment.
Treatment with bacteria
In 2013, scientists from Albert Einstein College of Medicine of Yeshiva University published findings of an experiment in which they used bacteria to carry radioisotopes commonly used in cancer treatment directly into pancreatic cancer cells.
The results showed that the incidence of secondary tumors went down dramatically. The cancer was less likely to spread, compared with other treatments, and there was no harm to healthy tissue.
There is no specific way to prevent pancreatic cancer, according to the American Cancer Society.
However, avoiding certain activities may reduce the risk.
- quitting smoking
- keeping a healthy weight
- eating plenty of fruits, vegetables, and whole grains
- consuming less red meat
Can vitamin supplements help?
Scientists have looked at the impact certain vitamins might have on the risk of pancreatic cancer.
Studies have linked vitamin D with a lower risk of several types of cancer, including pancreatic cancer. However, scientists still need to carry out large research studies to confirm whether or not vitamin D can help prevent pancreatic diseases.
Consuming B vitamins such as B12, B6, and folate in food — but not in pill or tablet form — may reduce the risk of pancreatic cancer.
Pancreatic cancer is difficult to diagnose and to treat, because it often does not produce symptoms until the later stages.
People who have risk factors that increase their chances of pancreatic cancer may wish to speak to their doctor about screening. An early diagnosis and early treatment will give the best outcome.