What is Cancer and How Does it Start?
Our body consists of millions of cells, all of which have a special function. The cells get their instructions from our genes which control the body’s creation of new cells and the repair and replacement of existing ones.
In some cases we can inherit a damaged gene from our parents. However damage to genes more often occurs during our life. A damaged gene may create cells that do not behave normally and create a tumour. A tumour is a new growth of tissue in or on the body. Tumours are either benign (harmless) or cancerous (malignant).
How does a malignant tumour harm the body?
Malignant tumours consist of cancer cells that can spread to other parts of the body if they are not treated. If they do spread they can create a new tumour which is a secondary cancer, called a metastasis.
Where is the pancreas?
The pancreas is an oblong-shaped gland in the abdomen. It is an important part if the digestive system. Because the pancreas is deep in the body, tumours are often not detected until they begin to interfere with digestion.
What does the pancreas do?
The pancreas secretes a fluid that helps food pass through the digestive system. It also produces insulin which regulates sugar in the blood. If the pancreas does not produce enough insulin, diabetes will develop.
What is pancreatic cancer?
Pancreatic cancer is not one disease and covers 20 or so different types of tumours. All of them basically fall into two classes.
Primary cancers are tumours that develop in the pancreas itself.
Metastatic cancers are tumours that develop in other parts of the body before spreading to the pancreas.
There are two general categories of tumours endocrine and non endocrine:
Of the non-endocrine the most common (although there are many others) is Adenocarcinomas which accounts for 75% of pancreas cancers. This type of tumour can become so large that it invades nerves and causes back pain. It frequently spreads to the liver – in which case it is generally not operable.
Endocrine: there are two types of tumours which are generally more benign than non-endocrine but are unpredictable in their impact. They account for around 1 per cent of pancreatic cancer patients.
What are the symptoms of pancreatic cancer?
Some common symptoms of pancreatic cancer are:
Distension of the abdomen : this is common in advanced stages of the disease and occurs when the cancer extends to the abdominal cavity.
Anorexia: loss of appetite is common when the disease is advance.
Cachexia: this is weight loss and or wasting of the muscles, it is caused by cancers that develop in other parts of the body and spread to the pancreas.
Diabetes: this occurs when the disease hinders the secretion of insulin.
Pain in back and abdomen: caused when the tumour expands and pushes against other organs.
Itching: this is a symptom of an obstruction in the pancreas.
Discoloured urine: caused by accumulation of bile in urine.
There are many symptoms of the disease but it is important to remember that a symptom does not automatically mean the cancer is present.
The only practical way to be sure is to check with your doctor.
How is pancreatic cancer diagnosed?
It is often hard to detect and diagnose pancreatic cancer because many of the symptoms, such as pain, jaundice (yellowing of the skin) and weight loss are not specific to the disease.
The single most used test is a CAT scan (computerized axial tomography) which x-rays the abdomen from different angles. A CAT scan should identify nine out of ten cancers and is used as the best way to determine whether there is a lump in the pancreas.
- Can determine if the liver ducts are blocked by the cancer by showing an increased bilirubin causing the yellow colour in the skin.
- Measurement of tumour markers. CA 19-9 is the most widely used marker. Levels of 37-200 u/L are elevated but when greater than 200 indicate more advanced cases. Sometimes very high levels are associated with benign disease and infection.
- MRCP used MRI to get a detailed picture of the pancreas and its ducts.
- EUS: An ultrasound machine is placed in the stomach to be close to the pancreas. This can see small lesions. Through this machine biopsies can be taken of small lesions.
What causes pancreatic cancer?
The cancer is a genetic disease. This means that patients can be born with the factors that cause it. But patients can equally acquire the factors that create the disease.
Factors that can trigger pancreatic cancer include:
- Smoking: Cigarette smoke includes cancer causing chemicals (carcinogens). Smoking in the late teens and early twenties may double or triple the risk of pancreatic cancer by two.
- Age: Over 80% of cases of pancreatic cancer occur in people over the age of 60.
- Diet: While the evidence is not conclusive, it seems that diets high in meat and fried foods are more dangerous than a diet rich in fruits and vegetables.
What is the impact of the disease?
In many cases pancreatic cancer can only be found when it is well advanced and as it progresses rapidly there is often very little that can be done to halt its progress.
Only around 20% of patients have a tumour which is resectable (the surgical removal of part of an organ). Of this group only 1-5% survive from three to five years.
What can doctors do?
If a doctor suspects pancreatic cancer they will refer patients for tests and send them to a specialist. If it is diagnosed, health professionals who will be involved include:
- Gastroenterologist: Diagnose pancreatic cancer and manage palliative care
- Hepatobiliary Surgeon: Specialise in surgery to the liver and bile ducts, where cancers originating in the pancreas may spread
- Medical Oncologist: Specialise in chemotherapy
- Radiation Oncologist: Give radiotherapy
- Endocrinologist: Diagnose and treat hormone disorders
What medical treatments are available?
There are two common types of therapy. Radiation: this stops cancer cells from dividing and growing. It can be used before or after surgery. It is also used in conjunction with chemotherapy to treat inoperable tumours.
What can surgery do?
Because pancreatic cancer is difficult to diagnose it is often advanced before it is discovered.
If the cancer is only in the pancreas and has not spread to other organs such as the liver or lungs, or to the lymph nodes or blood vessels surgery is possible. In cases where it has spread to lymph nodes that can be surgically removed an operation is still feasible.
However if the cancer has spread to other organs or distant lymph nodes, in most cases surgery cannot eradicate the disease.
Where surgery cannot cure the disease it can help reduce pain to improve a patient’s quality of life.
What are the stages of the disease?
Doctors use a four stage system to chart the course of pancreatic cancer. It is called the 'TNM system' (T = tumour, N = nodes, M = metastases). T followed by a number between 1 and 4 states the stage of the tumours development in the pancreas and other organs. The higher the number the further the cancer has spread.
N followed by 0 means that lymph nodes near the tumour are not colonised by it. N followed by 1 means this has occurred. Lymph nodes are important because they filter bacteria to stop them entering the bloodstream.
M followed by 0 means the cancer is confined to the pancreas. M1 means it has spread beyond it.
The treatment doctors recommend depends on the stage of the cancer measured by this system.
How can diet and exercise help if I have the disease?
Pancreatic cancer causes loss of appetite and reductions in weight and the side effects of chemotherapy and radiotherapy add to these problems. Despite this, it is important to keep calorie consumption up during treatment. One option is to eat smaller meals or snacks more frequently than three large meals. Foods should also be appealing whether or not they are high in fat.
While exercise may be difficult it is important to maintain some moderate physical activity at least three times a week. After surgery exercise can reduce fatigue and increase a patient’s sense of well being.
How is pain managed?
Palliative care techniques to control pain are particularly important for patients who cannot be cured but should not have to endure unavoidable pain.
Tumours can cause pain in the abdomen and in the lower back. Most pain is well controlled with oral medication. Medication to control back pain can be injected into the nerves of the back.
Palliative surgery can also help alleviate jaundice, nausea and vomiting for patients with advanced tumours in the head of the pancreas. One operation is a double bypass of the bile duct and the stomach.
Can alternative medicines help?
Complementary therapies, such as herbal medicine, vitamin and mineral supplements and special diets may help to manage symptoms but they are scientifically untested and there is definitely no evidence that they can cure pancreatic cancer. Complementary therapies should only be used with your doctor’s full knowledge and advice.
What questions should every patient ask their doctor?
Patients have a right to expect their doctors to answer questions about the disease and its treatment.