Pancreatic Cancer

Pancreatic cancer is a type of cancer that originates in the pancreas, a glandular organ located behind the stomach. The pancreas plays a vital role in the digestive system by producing enzymes that aid in the breakdown of food and hormones that regulate blood sugar levels. Pancreatic cancer arises when abnormal cells in the pancreas grow uncontrollably, forming tumours that may invade nearby tissues and metastasise.

What is Pancreatic Cancer?

Pancreatic cancer is a malignant growth that originates in the pancreas, a vital gland situated in the abdomen. The pancreas serves two primary functions: producing digestive enzymes to aid in food breakdown and secreting hormones, such as insulin and glucagon, to regulate blood sugar levels. When cancerous cells develop within the pancreas, they multiply uncontrollably, forming a tumour that can interfere with the organ's normal function. The absence of specific symptoms in the early stages of pancreatic cancer often leads to a delayed diagnosis, making it a particularly challenging condition to treat effectively. Understanding tumour biology, staging, and resectability is essential for guiding management (Mizrahi et al., 2020).

Pancreatic cancer is classified into two main types based on the cells from which the tumours originate. These include:

• Exocrine tumours: These are the most common form of all pancreatic cancers. They start in the exocrine cells of the pancreas that produce digestive enzymes. The main subtypes of exocrine tumours include:
• Adenocarcinoma: This is the most prevalent type and develops from the cells lining the pancreatic ducts.
• Acinar cell carcinoma: A rare form that causes the pancreas to produce excessive amounts of lipase, an enzyme that breaks down fats.
• Intraductal papillary-mucinous neoplasm (IPMN): A tumour that grows from the main pancreatic duct or its branches. Although initially benign, IPMNs, particularly those involving the main duct, carry a significant risk of progressing to invasive carcinoma.
• Mucinous cystic neoplasm with invasive adenocarcinoma: This uncommon type is mostly seen in women. These tumours are cystic in nature and contain thick fluid.
• Pancreatic neuroendocrine tumours (PNETs): They develop from the abnormal growth of endocrine cells in the pancreas, which are responsible for producing hormones that regulate blood sugar levels. PNETs tend to grow more slowly compared to exocrine tumours. 

Pancreatic cancer often doesn't cause noticeable symptoms in its early stages, making it challenging to detect. However, some early signs to be aware of include:

• Fatigue
• Unexplained weight loss
• Abdominal pain or discomfort
• Loss of appetite
• Nausea and vomiting
• Jaundice (yellowing of the skin and eyes)
• Dark urine and pale stools; steatorrhoea (greasy, foul-smelling stools due to fat malabsorption)

It's important to note that these symptoms can also be caused by other conditions, so it's essential to consult a doctor for an accurate diagnosis. As the disease progresses, additional symptoms may develop.

Pancreatic cancer can be difficult to detect early due to its often subtle symptoms. As the disease progresses, various signs become more apparent. The pancreatic cancer symptoms include:

• Jaundice: One of the most noticeable symptoms is jaundice, which causes the skin and eyes to turn yellow. This occurs when the tumour blocks the bile duct, leading to a buildup of bilirubin in the bloodstream.
• Abdominal pain: Patients may experience persistent or intermittent abdominal pain, which can radiate to the back. This discomfort arises from the tumour’s impact on surrounding tissues and organs.
• Unexplained weight loss: Significant weight loss without an obvious cause is common. This may result from reduced appetite, increased energy expenditure, and difficulties in nutrient absorption.
• Digestive issues: Symptoms such as nausea, vomiting, and changes in stool colour or consistency often arise. These issues are due to the cancer’s effect on the digestive system and enzyme production.
• Fatigue: Chronic fatigue is prevalent, with patients feeling unusually tired or weak despite adequate rest.
• Elevated blood sugar levels: New-onset diabetes or worsening glycaemic control may be an early indicator, particularly in older adults.
• Ascites: In advanced cases, fluid accumulation in the abdominal cavity, known as ascites, can cause noticeable swelling and discomfort, further impacting the patient’s quality of life.

Staging is a method used to describe the extent of pancreatic cancer based on its size and spread. The TNM staging system and the numerical system are employed to characterise the stages of pancreatic cancer.

1. TNM Staging System

The TNM staging system assesses the tumour's size and extent (T), the involvement of nearby lymph nodes (N), and the presence of metastasis (M).

• T categories: These describe the size of the primary tumour and whether it has grown outside the pancreas:
  • TX: The main tumour cannot be assessed.
  • T0: There is no evidence of a primary tumour.
  • Tis: Abnormal cells are found in the lining of the pancreas.
  • T1: The tumour is limited to the pancreas and is 2 centimetres or smaller.
  • T2: The tumour is larger than 2 centimetres but still confined to the pancreas.
  • T3: The tumour is larger than 4 cm but does not involve major arteries (Tempero et al., 2024).
  • T4: The tumour involves major arteries such as the celiac axis, superior mesenteric artery (SMA), or common hepatic artery.
• N categories: These indicate whether the cancer has spread to lymph nodes near the pancreas.
  • N0: There is no evidence of lymph node involvement.
  • N1: The cancer has spread to nearby lymph nodes.
  • N2: The cancer has spread to more distant lymph nodes.
• M categories: These indicate whether the cancer has metastasised to other parts of the body.
  • M0: The cancer has not spread to distant organs or lymph nodes.
  • M1: The cancer has spread to distant organs or lymph nodes.

2. Numerical Stages

The numerical staging system categorises pancreatic cancer into five main stages:

• Stage 0: Abnormal cells are found in the lining of the pancreas (Tis, N0, M0).
• Stage IA: The tumour is limited to the pancreas and is 2 centimetres or smaller (T1, N0, M0).
• Stage IB: The tumour is limited to the pancreas and is larger than 2 centimetres (T2, N0, M0).
• Stage IIA: The tumour extends beyond the pancreas but not into nearby major blood vessels or nerves (T3, N0, M0).
• Stage IIB: The tumour is of any size and has spread to nearby lymph nodes but not to distant sites (T1-3, N1, M0).
• Stage III: The tumour extends into nearby major blood vessels or nerves (T4, any N, M0).
• Stage IV: The cancer has spread to distant organs or lymph nodes (any T, any N, M1).

Understanding the staging of pancreatic cancer is crucial for determining the most appropriate treatment options and assessing the prognosis for patients diagnosed with this condition.

Pancreatic cancer is fundamentally a disease caused by damage to the DNA, which can occur through various mechanisms. The primary causes can be divided into three categories:

• Inherited mutations: Pancreatic cancer can be inherited due to genetic mutations passed from parents. For example, inherited variants in genes like BRCA2, BRCA1, and PALB2 increase the risk of pancreatic cancer.
• Behavioural factors: Certain behaviours, such as smoking, can damage DNA and increase the risk of pancreatic cancer. Smoking doubles the risk and is the leading preventable cause of the disease.
• Random DNA copying errors: DNA copying errors can occur during cell division, leading to genetic mutations that can cause pancreatic cancer.

Several risk factors contribute to the development of pancreatic cancer:

• Age (most diagnoses occur after age 60)
• More common in men than in women
• Higher incidence in African Americans than in whites, Asians, or Hispanics
• Type 2 diabetes
• Pancreatic cystic tumours
• Excessive consumption of red and processed meats
• Exposure to dry-cleaning and metalworking chemicals
• Smoking
• Chronic pancreatitis
• A family history of pancreatic cancer (Mizrahi et al., 2020)

Who's at Risk?

Certain individuals are at higher risk for developing pancreatic cancer:

• Those over 60 years old
• Current or former smokers
• Individuals diagnosed with diabetes, particularly type 2 diabetes
• People who are obese or overweight
• Those from racial groups with a higher incidence, such as Black people
• Individuals with a family history of pancreatic cancer
• People diagnosed with chronic pancreatitis
• Those who consume a diet high in fat or processed foods

Pancreatic cancer can lead to several complications that may affect a person's quality of life and overall health. Some of these complications include:

• Jaundice: The tumour grows and obstructs the bile duct, and bilirubin can accumulate in the blood, leading to yellowing of the skin and eyes.
• Pain: Pancreatic cancer can cause abdominal pain that radiates to the back, often due to the tumour pressing on nearby nerves or organs.
• Weight loss: Unintended weight loss is a common symptom of pancreatic cancer, often due to loss of appetite or the inability to digest food properly.
• Diabetes: Pancreatic cancer can cause diabetes or worsen pre-existing diabetes by damaging the insulin-producing cells in the pancreas.
• Blood clots: Pancreatic cancer increases the risk of developing blood clots in the legs (deep vein thrombosis) or lungs (pulmonary embolism).
• Digestive problems: Pancreatic exocrine insufficiency leads to malabsorption, steatorrhoea, nausea, and weight loss

While there is no guaranteed way to prevent pancreatic cancer, adopting certain lifestyle changes can help reduce the risk. These include:

• Avoid smoking: Quitting smoking or never starting is one of the most effective ways to reduce the risk of pancreatic cancer.
• Maintain a healthy weight: Adopting a balanced diet and engaging in regular physical activity can help maintain a healthy weight and reduce the risk of obesity-related pancreatic cancer.
• Eat a healthy diet: Consume a diet rich in fruits, vegetables, whole grains, and lean proteins while limiting the intake of high-fat, processed, and smoked meats.
• Manage diabetes: If you have diabetes, work with your healthcare provider to effectively manage your blood sugar levels through medication, diet, and exercise.
• Be aware of family history: If you have a family history of pancreatic cancer, discuss your risk with your doctor and consider genetic counselling to assess your individual risk and potential preventive measures.

Diagnosing pancreatic cancer typically involves a combination of blood tests, imaging studies, and a biopsy. These include:

• Computed tomography (CT) scan: CT scans create detailed cross-sectional images of the abdomen, helping to identify tumours and their locations.
• Magnetic resonance imaging (MRI): MRI uses magnetic fields and radio waves to produce detailed images of the pancreas, providing additional information about the tumour's size and spread.
• Positron emission tomography (PET) scan: PET scans involve injecting a radioactive tracer to highlight areas of high metabolic activity, which can indicate cancerous growths.
• Endoscopic ultrasound (EUS): This technique uses an endoscope with an ultrasound probe to obtain high-resolution images of the pancreas and nearby structures.
• Blood tests: Tumor markers such as CA 19-9 and CEA may be elevated, but they are not diagnostic and may also rise with benign conditions.
• Biopsy: It involves examining a tissue sample from the pancreas under a microscope to confirm the diagnosis and determine the type and stage of the tumour. 

Early detection of pancreatic cancer is challenging due to the often subtle and late-appearing symptoms. Being aware of potential early signs and undergoing regular check-ups can be crucial in managing the disease more effectively.

The treatment of pancreatic cancer focuses on a combination of chemotherapy, targeted therapy, radiotherapy, and, in selected cases, surgery to shrink tumours, control symptoms, and extend survival. Here are the treatment options for pancreatic cancer:

1. Surgery

Surgery is the only potentially curative treatment and is recommended for resectable or borderline-resectable tumors. Procedures include the Whipple procedure (pancreaticoduodenectomy), distal pancreatectomy, and total pancreatectomy (Kleeff et al., 2022).

2. Taxanes

Taxane-based therapy is a cornerstone in treating advanced pancreatic cancer due to its ability to halt tumour cell division.

• Paclitaxel: It stabilises microtubules in cancer cells, preventing them from dividing. Often used in combination with gemcitabine, it has shown improved survival and tumour response in metastatic disease.

3. Kinase Inhibitors

Kinase inhibitors block signalling pathways essential for cancer growth and angiogenesis, making them effective in specific tumour subtypes.

• Everolimus: It targets the mTOR pathway and is used in advanced pancreatic neuroendocrine tumours (PNETs).
• Erlotinib: This EGFR inhibitor is sometimes used with gemcitabine to hinder tumour cell proliferation.
• Sunitinib: Particularly effective in PNETs, it blocks multiple tyrosine kinases involved in tumour blood vessel formation and growth.

4. Pyrimidine Antagonists

These agents mimic natural nucleotides and interfere with DNA and RNA synthesis, thereby slowing the replication of cancer cells.

• Capecitabine: An oral prodrug of 5-FU, often used with radiation or as maintenance therapy.
• Gemcitabine: A first-line chemotherapy drug that integrates into DNA strands, halting their elongation (Tempero et al., 2024).
• 5-Fluorouracil (5-FU): Used intravenously or in combination regimens, it disrupts nucleotide metabolism and tumour cell proliferation.

5. Topoisomerase-1 Inhibitors

These medicines impair the repair of DNA by blocking topoisomerase enzymes, leading to tumour cell death.

• Irinotecan: Often part of FOLFIRINOX (a multi-drug regimen), it is used in advanced or metastatic pancreatic cancer for greater treatment efficacy.

6. Poly (ADP-Ribose) Polymerase (PARP) Inhibitors

PARP inhibitors are particularly useful in patients with hereditary BRCA mutations by targeting DNA repair mechanisms.

• Olaparib: Used in maintenance therapy for metastatic pancreatic cancer with germline BRCA1/2 mutations, it delays disease progression by preventing DNA repair in cancer cells.
• Pembrolizumab may be used for pancreatic cancers that are microsatellite instability-high (MSI-H) or mismatch-repair deficient (dMMR).

7. Radiotherapy

External-beam radiation therapy may be used with chemotherapy for locally advanced disease or for symptom relief. Peptide receptor radionuclide therapy (e.g., Lutetium Lu 177) is used specifically for metastatic pancreatic neuroendocrine tumors expressing somatostatin receptors

It is crucial to consult a doctor if you experience any symptoms that may indicate pancreatic cancer, such as persistent abdominal pain, unexplained weight loss, jaundice, or changes in bowel habits. Early detection and prompt treatment can significantly improve the chances of a successful outcome. If you have a family history of pancreatic cancer or other risk factors, such as chronic pancreatitis or diabetes, it is essential to discuss your concerns with a doctor. They can recommend appropriate screening tests and guide risk reduction strategies.

• Pancreatic cancer is a serious condition that requires prompt diagnosis and treatment.
• Diagnosis involves blood tests, imaging studies, and a biopsy to determine the type and stage of cancer.
• Management options include surgery, chemotherapy, radiation therapy, and palliative care, depending on individual factors.
• Various medications are used to treat pancreatic cancer, including gemcitabine, capecitabine, erlotinib, nab-paclitaxel, and FOLFIRINOX.
• Consult a doctor promptly if you experience any signs or symptoms that could indicate pancreatic cancer.
• Early detection, regular check-ups, and a healthy lifestyle are key to improving pancreatic cancer outcomes and reducing risk.