Pancreatic cancer forms in the tissues of the pancreas — an organ in the abdomen that lies behind the lower part of the stomach. The pancreas releases enzymes that help in digestion and produces hormones that help manage the blood sugar.
Several types of growths can occur in the pancreas, including non-cancerous and cancerous tumors. The most common type of cancer begins in the cells that line the ducts which carry digestive enzymes out of the pancreas — pancreatic ductal adenocarcinoma.
The incidence of pancreatic cancer in India is low (0.2 – 1.8 per 100,000 in women and 0.5 – 2.4 per 100,000 in men). It is higher in urban male population of northern and western parts of India.
Types of pancreatic cancer
There are several types of pancreatic cancer, however the vast majority (more than 90 per cent) of all diagnoses are for adenocarcinoma of the pancreas. The cancer types can be largely divided into two categories: neuroendocrine pancreatic cancer and exocrine pancreatic cancer, which includes adenocarcinoma. Each category has many cancer types that may vary in their prognosis and symptoms.
- Neuroendocrine pancreatic cancer – Pancreatic neuroendocrine tumors (NETs) form from the cells in the endocrine gland of the pancreas, which secretes the glucagon and hormones insulin into the bloodstream to regulate blood sugar. They are also known as endocrine or islet cell tumors. NETs are rare, making up less than 5 per cent of all pancreatic cancer cases.
- Exocrine (Nonendocrine) pancreatic cancer – Exocrine pancreatic cancer begins from the exocrine cells, which make up the ducts and exocrine gland of the pancreas. The gland secretes enzymes that help break down fats, carbohydrates, acids, and proteins in the duodenum.
Several types of exocrine pancreatic cancers make up more than 95 per cent of all cancers of the pancreas. They include:
- Adenocarcinoma – Also known as ductal carcinoma, it is the most common type of pancreatic cancer. The cancer occurs in the lining of the ducts in the pancreas. It is also possible for adenocarcinoma to form from the cells that create pancreatic enzymes. When this happens, it is called acinar cell carcinoma, which accounts for 1 per cent to 2 per cent of exocrine cancers.
- Squamous cell carcinoma – It is an extremely rare nonendocrine cancer of the pancreas which forms in the pancreatic ducts, and is made only of squamous cells, which are not usually seen in the pancreas.
- Adenosquamous carcinoma – This rare type of pancreatic cancer indicates 1 per cent to 4 per cent of exocrine pancreatic cancers. These tumors show characteristics of both squamous cell carcinoma and ductal adenocarcinoma.
- Colloid carcinoma – Another rare type, colloid carcinomas represents 1 per cent to 3 per cent of exocrine pancreatic cancers. These tumors usually grow from a type of benign cyst called an intraductal papillary mucinous neoplasm (IPMN). It is not as likely to spread and is also much easier to treat than other pancreatic cancers. It also has a better prognosis.
Symptoms of pancreatic cancer often does not occur until the disease is metastasized. They may include:
- Loss of appetite or unintended weight loss
- Abdominal pain that radiates to the back
- Light-colored stools
- Yellowing of the skin and the whites of the eyes (jaundice)
- Dark-colored urine
- Blood clots
- New diagnosis of diabetes or existing diabetes that is becoming more difficult to control
Causes and diagnosis
Pancreatic cancer occurs when DNA in a cell in the pancreas is damaged. A single cancer cell grows and divides quickly, becoming a tumor that does not go along with the body’s usual system. Without treatment, cells from the tumor spread through the lymph or blood system.
For diagnosis, a doctor will ask about symptoms, take a medical and family history, and carry out a physical exam. He will probably also recommend some tests. The doctor will pay special attention to common symptoms like:
- Weight loss
- Back or abdominal pain
- Poor appetite
- Gallbladder enlargement
- Digestive problems
- Pulmonary embolism, blood clots, or deep venous thrombosis (DVT)
- Fatty tissue abnormalities
- Swelling of lymph nodes
- Fatty stools
Trousseau’s sign, atypical diabetes mellitus and recent pancreatitis may also indicate that pancreatic cancer is present.
Some laboratory tests may include:
- Blood tests
- Stool tests
- Urine tests
Blood tests can find a chemical that pancreatic cancer cells release into the blood. Whereas liver function tests look for bile duct blockage.
Some imaging tests may include:
- X-ray, mostly with a barium meal
- Ultrasound or endoscopic ultrasound
- MRI, CT, or PET scans
- An angiogram
Imaging tests are used to look for a tumor, find out how far it has spread, and to help see if the cancer treatment is working.
A biopsy can confirm a diagnosis. The doctor removes a small sample of tissue for analyzing under the microscope.
Stages and treatment options
Pancreatic cancer is broken into four stages with stage 1 being the earliest stage (stage 0 is not counted) and stage 4 being the most advanced.
- Stage 0 – Cancer is detected only in the lining of the pancreatic ducts. This stage is also called carcinoma in situ.
- Stage 1 – Cancer has been detected and is in the pancreas only. It is further divided into:
- Stage 1A – The tumor is 2 cms or smaller.
- Stage 1B – The tumor is larger than 2 cms.
- Stage 2 – Cancer may have spread or advanced to the nearby tissue and organs and lymph nodes near the pancreas. It has sub-types like:
- Stage 2A – Cancer has spread to the nearby organs and tissue but has not spread to the nearby lymph nodes.
- Stage 2B – Cancer has spread to the nearby lymph nodes and may have spread to other nearby organs and tissue.
- Stage 3 – Cancer has spread to the major blood vessels near the pancreas and may have also spread to the nearby lymph nodes.
- Stage 4 – Cancer may be of any size and has spread to the distant organs, like the lung, liver and peritoneal cavity. It may have also spread to the organs and tissues near the pancreas or to lymph nodes. This stage is also termed as end stage pancreatic cancer.
Treatment for pancreatic cancer depends on the location and stage of the cancer as well as on the overall health and personal preferences. Treatments may include surgery, chemotherapy, radiation or a combination of these.
Operations done in people with pancreatic cancer include:
- Surgery for tumors in the pancreatic body and tail. The doctor may also need to remove the spleen.
- Surgery to remove the entire pancreas – In some cases, the entire pancreas may need to be removed. It is called total pancreatectomy. One can live relatively normally without a pancreas but do need enzyme replacement and lifelong insulin.
- Surgery for tumors in the pancreatic head – If the cancer is located in the head of the pancreas, one may consider an operation known as Whipple procedure (pancreaticoduodenectomy).
The Whipple procedure is a difficult operation to remove the head of the pancreas, the gallbladder, the first part of the small intestine (duodenum), part of the bile duct and nearby lymph nodes. In few cases, part of the colon and stomach may also be removed. The doctor reconnects the remaining parts of the stomach, pancreas and intestines to allow you to digest food.
- Surgery for tumors affecting the nearby blood vessels – People with advanced pancreatic cancer are not considered for the Whipple procedure or other surgeries if their tumors involve the nearby blood vessels. At some places, doctors may offer pancreatic surgery treatments that include removing and reconstructing the affected blood vessels.
It uses drugs to help destroy cancer cells. The drugs can be injected into a vein or taken orally. It can also be combined with radiation therapy which is known as chemoradiation. It is typically used to treat cancer that has not spread beyond the pancreas to the other organs.
Radiation therapy uses high-energy beams, like those from protons and x-ray, to kill cancer cells.
Side effects of treatment
Pancreatic cancer treatments can cause several side effects. These may include:
- Vomiting and nausea
- Stool changes (digestive problems like diarrhea or constipation)
- Mouth sores
- Taste and appetite changes
- Skin and nail changes
Survivorship and prevention
Pancreatic cancer survivors may develop a new ‘normal’ while taking time to recover. They may have permanent scars on the bodies or find it more difficult to do certain things. Unfortunately, many pancreatic cancer patients are never cured of their disease. Even after a successful surgery, the cancer may recur. Hence it is important to discuss any health concerns and symptoms with the doctor. While staying informed about the disease and treatment is important, it also is essential to try to regain the personal balance by exercising, eating healthy, reducing stress and finding sources of support. Also keep up with other health screenings such as colonoscopies and mammograms.
There is no definite way to prevent pancreatic cancer. However certain measures may reduce the risk. These include:
- Keeping a healthy weight
- Quitting smoking
- Eating plenty of vegetables, fruits, and whole grains
- Consuming less red meat
- Consuming B vitamins such as B6, B12, and folate in food may reduce the risk
- Use of vitamin D and Vitamin B12 could also be beneficial
People who have risk factors that increase the chances of pancreatic cancer should speak to a doctor about screening. An early diagnosis and treatment will give the best outcome.