The pancreas is an important endocrine gland that produces several important hormones including insulin. Pancreatic cancer refers to a condition wherein malignant cells formulate in the organ. There are two types of cells in the pancreas namely exocrine which secretes digestive juices and endocrine which produce hormones.
The types of pancreatic cancer can be demarcated into:
- Exocrine Cancers : These include the most widely encountered type of pancreatic cancer called adenocarcinoma, occurring in 85% of the patients. Around 60-70% of the adenocarcinomas are present in the pancreatic head.
The second most occurring form of pancreatic cancer is the acinar cell carcinoma. This type starts in the cell clusters that produce enzymes. This forms almost 5% of all exocrine cancer cases. This type results in excessive production of digestive juices which might lead to rashes on the skin and joint pains.
Another type of exocrine pancreatic cancer is Cystadenocarcinoma which accounts for roughly 1% of the cases, and this type also has a better rate of accurate prognosis than the other cases.
Another type of exocrine cancer is Pancreatoblastoma which is a rare form of pancreatic cancer. This type usually occurs in childhood and has a good prognosis.
- Neuroendocrine Cancers : These are in the form of tumours that might be benign or malignant. These originate from the neuroendocrine cells in the body which integrate the nervous system and the endocrine system in the body. These are further classified into functioning and non-functioning.
- Age: Increasing age is probably the biggest risk factor for developing pancreatic cancer. Most of the cases develop after the age of 60, whereas cases before the age of 40 are not very common.
- Gender : Pancreatic cancer has been found to be more common in men than in women.
- Heredity: Around 5-10% of cases of pancreatic cancer occur in people having a family history of the disease. There is a greater risk if greater than one first degree relative suffered from the disease, and there is a moderate risk if the first-degree relative had developed the disease before they reached the age of 50. Many individuals undergo screening for the early detection of pancreatic cancer on a research basis. Some individuals opt for the removal of their pancreas to prevent the development of cancer in the future.
Some other rare hereditary disorders have also been associated with pancreatic cancer. These include Peutz-Jeghers syndrome which is extremely rare but is a very big risk factor, autosomal recessive ataxia-telangiectasia, autosomal heredity mutations in the BRCA2 and PALB2 gene, familial adenomatous polyposis and dysplastic nevus syndrome which occurs due to mutations in CDKN2A tumour suppressor gene.
- Smoking : Smoking cigarettes is the most widely known avoidable risk for the development of pancreatic cancer. Long-term smokers usually are at double the risk, the risk increases with the number of cigarettes smoked in a day and the number of active smoking years. After the individual quits smoking, it takes approximately 20 years for the risk to return to that of a normal person.
- Chronic pancreatitis : triples the risk of pancreatic cancer. People with a family history of pancreatitis are at a higher risk than others.
- Obesity : Risk of pancreatic cancer is increased by almost half in people with a Body Mass Index (BMI) of more than 35.
- Diabetes Mellitus : Newly acquired diabetes is often deemed to be an early sign of pancreatic cancer. Individuals suffering from Type 2 diabetes for more than 10 years have 50% more risk as compared to people who do not have diabetes.
- A certain type of food items : Some food items like red meat, meat cooked at high temperatures and processed meat show evidence of marginally more risk than other items.
- Alcohol : Excessive alcohol is a primary cause of chronic pancreatitis which leads to the development of pancreatic cancer. Though, there is no considerable evidence of the association between alcohol and pancreatic cancer.
The symptoms of pancreatic cancer are not recognizable in the early stages which is a reason why the disease is not recognized until the problem has spread beyond the pancreas. This is a primary reason why the disease has an abysmal survival rate.
The common symptoms of pancreatic cancer are:
- Jaundice : Yellowing of the skin and the whites of the eyes and darkened urine are signs to look for. This occurs when cancer in the pancreatic head disrupts the bile duct running through the pancreas.
- Diabetes : Approximately 50% of the patients with adenocarcinoma have been known to have diabetes when they are diagnosed. Though diabetes is considered to be a risk factor, sometimes cancer might itself cause diabetes in which case it becomes a sign of early detection.
- Unexplained weight loss : Weight loss resulting from loss of appetite or exocrine dysfunction which results in poor digestion is a sign of pancreatic cancer.
- Pain in the upper abdomen : The location or the origin point of the pain can help in determining the part of the pancreas where a tumour is situated. The pain might become severe with the severity increasing at night. Abdominal pain is the major symptom in around two-thirds of the patients.
- Nausea : A tumour in the pancreas tends to compress the adjoining organs which disturb the digestive process making it difficult for the stomach to empty often resulting in nausea and feeling full. Constipation is also a common symptom.
Blood clots and enlarged gallbladder are some other symptoms of the disease.
Also, Endocrine cancer presents symptoms which are related to the excess hormones produced. These tumours include:
- Glucagonomas: Increase in glucose levels can show symptoms of diabetes and skin changes, namely a rash called necrolytic migratory erythema.
- Gastrinomas: Such tumours cause excessive production of acid by the stomach leading to ulcers, anaemia and black stools.
- Insulinomas: These lower blood glucose levels and result in weakness, confusion etc.
- Somatostatinomas: This leads to the overregulation of certain hormones which produces symptoms of diarrhoea, diabetes, jaundice and belly pain among others.
- Palomas : These types affect the exocrine as well the endocrine functions which lead to enlarged liver, watery diarrhoea and abdominal pain.
- Carcinoid: These exhibit symptoms like flushing of the skin, diarrhoea, wheezing etc. In some cases, there is damage to the valves in the heart which causes weakness, shortness of breath and heart murmur.
The symptoms of pancreatic cancer do not come to forth in the early stages of the ailment, are mostly are not distinctive to this particular disease. The signs at the time of diagnosis depend on the location of a tumour in the pancreas.
Majority of people with pancreatic cancer visit their physician with signs of non-specific symptoms like weight loss, fatigue, increase in abdominal fluid, gastrointestinal symptoms etc. These are followed by a physical examination, X-Ray, Blood Tests and Ultrasound. If the individual suffers from pancreatic cancer, the chances of finding some abnormality through an ultrasound are around 70-75%.
CT Scan and endoscopic ultrasounds are some of the imaging techniques that are used to confirm the diagnosis and to assess whether it is possible to remove a tumour by a surgery. Ultrasound of the abdomen is less sensitive and will most probably not be able to detect minor tumours but can be used to detect cancer that has spread beyond the pancreas. It can be used as a fast and an inexpensive first method of examination before other methods are used.
In case a mass is seen, a biopsy needs to be performed to make the diagnosis. Different methods are used in order to perform a biopsy to obtain the tissue from the affected part of the organ. If it is discovered that cancer has spread to the liver, a needle biopsy is performed. In case the tumour has not spread beyond the pancreas, a direct biopsy is performed with the help of a CT scan. Sometimes a direct biopsy is also performed by putting an endoscope down the throat to the intestines. A tissue sample is needed to diagnose the disease with certainty and the doctors try to do it at the earliest and with the most effective technique.
Liver function tests which can show bile duct obstruction are also used. Blood tests known as tumour markers can also be used. In people with pancreatic cancer, these blood tests show elevated levels. However, the test is not specific to pancreatic cancer.
If a resectable pancreatic cancer is identified at the early stages and has not spread beyond the pancreas surgery can be performed. This is a potentially curative treatment for the disease. It is imperative that the procedure is performed at a medical institution with experience of performing the surgery as it is a big and complicated procedure. The surgeons should select the patients to be treated carefully based on who can get through it safely. The mortality from the surgery is less than 4%. Complications include the sluggish return of bowel function, anaemia and leakage of intestines/ducts connected via the surgery.
In case of locally advanced unresectable pancreatic cancer, a combination of chemotherapy in low doses along with radiation to the pancreas and the other affected tissues is used. These radiation treatments are used to minimize the risk of cancer growing locally and thereby causing localized symptoms. The treatment is prescribed for 5 weeks (Monday-Friday). Simultaneous chemotherapy lowers the risk of cancer spreading to other areas. After completion of the radiation treatment and the patient’s recovery, more chemotherapy is generally recommended.
In the case of metastatic pancreatic cancer, where cancer has spread beyond the pancreas to other surrounding organs it becomes a major problem throughout the system. In this situation, chemotherapy is most effective as it can target cancer in the areas it has spread throughout the body. The severity of the chemotherapy depends on the overall health condition of the patient. Unfortunately, the benefits of chemotherapy in pancreatic cancer patients are not very high. It extends the lifespan of the average patient by a few months only.
The side effects depend on the treatment received by the patient. Radiation causes side effects like nausea, diarrhoea and fatigue.
Side effects of chemotherapy include loss of appetite, diminishing strength of the immune system, hair loss, fatigue etc.
Reducing smoking increased consumption of healthy vegetables, whole grains and fruits, maintaining a healthy weight and reducing consumption of meat which is processed and red meat is recommended. Although, there is no direct evidence that this reduces the risk of pancreatic cancer.
At this point in time, there is no screening method for the general population. Targeted screening of individuals with first level family members being diagnosed with pancreatic cancer or in people with genetic risk factor is being pursued.
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