Pancreatic cancer

According to world health organization, worldwide, around 338,000 new cases with pancreatic cancer diagnosed in 2012. It is the 12th most common cancer worldwide. Pancreatic cancer incidence rates are highest in Northern America and lowest in Middle Africa, but this partly reflects varying data quality worldwide.

Overview

 

Pancreatic cancer is a disease in which malignant cells form in the tissues of the pancreas. There are types of pancreatic cancer are pancreatic exocrine cancer and endocrine pancreatic tumors, and other rarer types of pancreatic cancer include pancreatoblastoma, sarcomas of the pancreas, and Lymphoma.

However, the cause of pancreatic cancer is unknown, but there are some factors may increase the risk of developing pancreatic cancer, such as age, gender, history of certain health conditions, genetics, and lifestyle.

Identified 3 distinct precursor lesions: pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN). PanINs are the microscopic precursor lesions less than 5 mm, defined as neoplastic epithelial proliferations in the small pancreatic ducts. PanINs are classified depending on their degree of differentiation to PanIN-1, PanIN-2, or PanIN-3.

Pancreatic cancer may not cause early signs or symptoms, but there are some symptoms may occur by pancreatic cancer, like pain in the back or stomach area, unexpected weight loss, jaundice is yellowing of the skin and whites of the eyes, nausea and vomiting, bowel changes , fever and shivering, and indigestion.

Usually, pancreatic cancer is diagnosed by tests and procedures, include physical exam and history, lab Tests (blood chemistry tests, tumor marker test), biopsy, and imaging Tests.

Treatment of pancreatic cancer depends on stage and location of cancer, include surgery, radiation, chemotherapy, and ablation or embolization Treatments. If untreated, some complications may occur of pancreatic cancer patients, such as weight loss, jaundice, pain, and bowel obstruction.

Quite smoking, maintain a healthy weight, and Limit alcohol use are ways may prevent pancreatic cancer .general health and grade of the pancreatic cancer that may effect of prognosis of pancreatic cancer.

According to world health organization, worldwide, around 338,000 new cases with pancreatic cancer diagnosed in 2012.

 

Definition

Pancreatic cancer is one of types of cancer, grow in the pancreas and caused by the abnormal and uncontrolled growth of cells in the pancreas, and begins in the cells that produce the juices forming a tumor. 

Subtypes

There are two subtypes of pancreatic cancer based on location of tumor, including:

1-Exocrine pancreatic cancer

Exocrine pancreatic cancers that they start in cells that produce pancreatic digestive juices. Tumors of the exocrine pancreatic gland that include:

  • Adenocarcinomas

Adenocarcinoma is the most common tumor in the pancreas. adenocarcinomas are start in the cells lining the ducts of the pancreas also called as ductal adenocarcinomas. Nearly all of adenocarcinomas are ductal adenocarcinomas. 

  • Rarer types

Rarer types of exocrine pancreatic cancer include:

  1. Cystic tumors

Presence of cyst or fluid filled sac in the pancreas. most pancreatic cysts are benign but some are cancerous.

 

  1. Cancer of the acinar cells

These tumors are generally diagnosed in people at a younger age. The acinar cells are located at the ends of the ducts and produce pancreatic juices.

 

2-Endocrine pancreatic tumors

Uncommon endocrine pancreatic tumors that start in the endocrine pancreas, made insulin and other hormones and released directly into the bloodstream. They are also called pancreatic neuroendocrine tumors (PNETS) or islet cells tumors. 

Two thirds of pancreatic endocrine tumors are called non functioning tumors as they don't produce any hormones, Most of these tumors are cancers (malignant). About a third of these tumors produce hormones, which can cause some strange symptoms. Most of these tumors are non-cancerous (benign).

They are named after the hormone they produce, include: 

  • Gastrinomas produce a hormone called gastrin.
  • Insulinomas produce insulin.
  • Somatostatinomas produce a hormone called somatostatin.
  • VIPomas produce a hormone called VIP.
  • Glucagonomas produce a hormone called glucagon. 

 

3- Other rare types.

There are other rare types of cancer of the pancreas, including:

  • Pancreatoblastoma

Very rare tumors occur in children. Pancreatoblastoma are sometimes linked with rare genetic conditions such as Beckwith-Wiedemann syndrome and familial adenomatous polyposis (FAP). 

 

  • Sarcomas of the pancreas

Sarcomas of the pancreas are extremely rare. Which that hold together the cells of the pancreas. 

 

  • Lymphoma

Lymphoma can develop in any part of the body. it is a cancer of the lymphatic system.

Causes

The exact cause of pancreatic cancer is unknown in most cases.  

Risk Factors

There are certain risk factors that may increase chances of developing pancreatic cancer.  Including:

1-age

The risk of developing pancreatic cancer increases after age 50 years. 

2- gender

Pancreatic cancer is more common in women than in men. 

3-Race

pancreatic cancer is more likely to develop in African Americans populations than in white population. 

4- history of certain health conditions

The health conditions such as diabetes, chronic pancreatitis (long-term inflammation of the pancreas), Cirrhosis of the liver, stomach ulcer and Helicobacter pylori infection (a stomach infection) may increase the risk of developing pancreatic cancer.

5-Family history

Pancreatic cancer seems to run in some families. 

6- Obesity

Obesity that can increase the risk of developing of pancreatic cancer. 

7- Genetics

Family history of genetic syndromes that can increase cancer risk, including a breast cancer syndrome (BRCA2 and PALB2), Lynch syndrome, familial atypical mole-malignant melanoma (FAMMM) syndrome, and the Peutz-Jeghers syndrome. 

8- Workplace exposure to certain chemicals

Exposure to certain chemicals may raise the risk of pancreatic cancer that used in the dry cleaning and metal working industries. 

9-Lifestyle

There are factors may increase the risk of developing of pancreatic cancer, but not all studies have found such links, and this is still being studied, including: 

  • Smoking: The risk of getting pancreatic cancer is about twice as high among smokers compared to those who have never smoked. 
  • Diet: A diet high in fat and low in fruits and vegetables can increase the risk of developing pancreatic cancer. 
  • Physical inactivity: lack of physical activity may increase pancreatic cancer risk.
  • Coffee: Some older studies have suggested that drinking coffee might increase the risk of pancreatic cancer.
  • Alcohol: use Heavy alcohol can lead to increase pancreatic cancer risk. 
Pathophysiology

Molecular and histopathological analyses of pancreas have identified three distinct precursor lesions arepancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN). PanINs are the microscopic precursor lesions less than 5 mm, defined as neoplastic epithelial proliferations in the small pancreatic ducts. PanINs are classified depending on their degree of differentiation to PanIN-1, PanIN-2, or PanIN-3. The progression from normal epithelium to invasive carcinoma has been proposed to follow a linear progression model, associated with accumulation of genetic alterations. 

Stages of pancreatic cancer

There are four stages of pancreatic cancer that based on spread of cancer in the pancreas, include:

  1. Stage 1: the cancer is completely inside the pancreas and hasn't spread anywhere else, and can be removed using surgery.
  2. Stage 2: the cancer has started to spread into surrounding tissues or nearby lymph nodes. May be remove the cancer by surgery.
  3. Stage 3: the cancer has spread into nearby large blood vessels or lymph nodes. This is called locally advanced cancer. Surgery may or may not be possible to remove the cancer at this stage.
  4. Stage 4: the cancer has spread to other areas of the body such as the liver or lungs. It is called advanced cancer. Surgery is not an option at this stage. 
Signs And Symptoms

In the early stages, a tumor in the pancreas doesn't usually cause any symptoms, which can make it difficult to diagnose.

Pancreatic cancer may cause signs and symptoms, including:

1-Pain in the back or stomach area.

2-Unexpected weight loss.

3- Jaundice is yellowing of the skin and whites of the eyes.

4- Nausea and vomiting.

5- Bowel changes.

6- Fever and shivering.

7- Indigestion.

8- Blood clots. 

9- Depression. 

10- Increase in blood sugar level (diabetes).

11- Fatigue and weakness.

12- Diarrhea.

13- Dark urine and clay-colored stools.

14- Itching of the skin. 

Diagnosis

Early diagnosis significantly increases the chances of recovery. More tests will be done to help to diagnosis the cancer. Including: 

1-Physical exam and history

Exam of the body to check signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken. 

 

2-Lab Tests

Laboratory tests can measure amounts of certain substances, include:

  • Blood chemistry tests: check the blood sample to measure the amounts of certain substances, such as bilirubin.
  • Tumor marker test: check the blood sample to measure the amounts of certain substances, such as CA 19-9, and carcinoembryonic antigen (CEA), made by organs, tissues, or tumor cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the body . 

 

  • Blood tests looking at the levels of certain pancreatic hormones can often help diagnose endocrine pancreatic tumors . Tests might be done to check blood levels of:

 

1-Hormones made by different types of endocrine pancreatic tumors cells, such as insulin, gastrin, glucagon, somatostatin, pancreatic polypeptide, and VIP (vasoactive intestinal peptide)

2- Chromogranin A (CgA)

3- Glucose and C-peptide (for insulinomas)

4- Serotonin or related chemicals such as 5-HIAA and 5-HTP, chromogranin A (CgA), neuron-specific enolase (NSE), substance P, and gastrin (check of carcinoid tumors).

 

3- Biopsy

 A biopsy is a procedure for remove small amount of tissue and look at it under microscope. 

 

4- Imaging Tests

Imaging tests that use to see pancreas and the surrounding organs and help to diagnose tumors and monitor their growth over time. Include:

1-MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI). 

2- CT scan (Computed tomography scan): This procedure is also called as computerized axial tomography. A procedure that makes a series of detailed pictures of areas inside the body to diagnose pancreatic cancer. A CT scan can help determine if surgery might be a good treatment option. A spiral or helical CT scan makes a series of very detailed pictures of areas inside the body using an x-ray machine that scans the body in a spiral path.

A special type of CT known as a multiphase CT scan or a pancreatic protocol CT scan is used to taking image of pancreas after intravenous injection. 

3- Ultrasound tests: use ultrasound tests to create images of organs such as the pancreas. There are two types of ultrasound image :

  • Abdominal ultrasound: Abdominal ultrasound used to make pictures of the inside of the abdomen. 
  • Endoscopic ultrasound (EUS): Endoscopic ultrasound test is more accurate than abdominal ultrasound and used to diagnostic pancreatic cancer.

4-Positron emission tomography (PET) scan: A procedure to find malignant tumor cells in the body, by injected small amount of radioactive glucose (sugar) into a vein. A PET scan and CT scan may be done at the same time, also called as PET-CT scan. This test can help to determine the stage (extent) of the cancer. 

5- Cholangiopancreatography: imaging test can look at the pancreatic ducts and bile ducts to see if they are blocked, narrowed, or dilated. 

6-Somatostatin receptor scintigraphy (SRS): can be very helpful in finding pancreatic neuroendocrine tumors (NETs). 

7- Angiography: X-ray test that looks for blood vessels. It can also show abnormal blood vessels in the area and finding out if a pancreatic cancer. 

Treatment

The treatment of pancreatic cancer depending on stage and location of the cancer, several ways to treat pancreatic cancer may include:

  • Surgery

Two types of surgery can be used for pancreatic cancer, include:

1-Potentially curative surgery: may use potentially curative surgery when the results of exams and tests suggest that it’s possible to remove all of the cancer.

2-Palliative surgery: can used palliative surgery when imaging tests show that the cancer is too widespread to be removed completely. This surgery is done to relieve symptoms or to prevent certain complications. 

  • Ablation or Embolization Treatments

Ablation or Embolization treatments are different ways of treatment of pancreatic cancer and used to help treat cancer that has spread to other organs.

1-Ablative treatments: Ablation refers to treatments with extreme heat or cold that destroy tumors. 

2- Embolization : Embolization treatment used for tumors in the liver that are too large to be treated with ablation by blocks the blood flow to cancer cells, causing them to die. 

 

  • Radiation Therapy

Radiation therapy by uses high-energy x-rays to help shrink tumor and relieve pain. 

 

  • Chemotherapy

Chemotherapy is a type of treatments that uses anti-cancer medicines to kill the cancerous cells in body or stop them multiplying. 

Complications

Progresses pancreatic cancer may cause some complications, include:

1-Weight loss.

Pancreatic cancer may cause weight loss due to some causes such as cancer treatments that cause nausea and vomiting or a tumor pressing on stomach may make it difficult to eat or may have difficulty processing nutrients from food because lack of digestive juices that produce from pancreas . 

2- Jaundice.

Jaundice is a result from blocks the liver's bile duct. Yellow skin and eyes, dark-colored urine, and pale-colored stools are symptoms and signs of Jaundice and usually occurs without abdominal pain.

3- Pain.

Pain that can become severe because growing tumor and may press on nerves of abdomen.

4-Bowel obstruction.

Pancreatic cancer that grows into or presses on the first part of the small intestine can block the flow of digested food from stomach into intestines and lead to bowel obstruction. 

Prevention

There is no sure way to prevent pancreatic cancer, but there are ways may lower risk of developing pancreatic cancer, such as:

1-Quite smoking.

Smoking is the most important risk factor for pancreatic cancer, so quitting smoking helps lower risk of developing pancreatic cancer.

2-Maintain a healthy weight.

Getting to and staying at a healthy weight may lower risk of developing pancreatic cancer. 

3-Limit alcohol use.

Heavy alcohol use can lead to conditions such as chronic pancreatitis and cirrhosis, which are known to increase pancreatic cancer risk. Heavy alcohol use has relations to pancreatic cancer in some studies but not in others. 

4-Limit exposure to certain chemicals in the workplace.

To reduce risk of developing pancreatic cancer by avoiding workplace exposure to certain chemicals. 

Prognosis

Prognosis of pancreatic cancer depends on how far the cancer has progressed. When diagnosed pancreatic cancer early there are better chance of successful treatment, which may be surgery. When diagnosed cancer it is advanced and is not suitable for surgery, and reduce chances of recovery. The general health and grade of the cancer that may effect of prognosis. 

Epidemiology

According to world health organization, worldwide, around 338,000 new cases with pancreatic cancer diagnosed in 2012. It is the 12th most common cancer worldwide. Pancreatic cancer incidence rates are highest in Northern America and lowest in Middle Africa, but this partly reflects varying data quality worldwide.