Cancer Type

pancreatic cancer Introduction

When pancreatic cells proliferate uncontrollably and invade other normal cells in the body, pancreatic cancer develops. Pathologically, approximately 90% of pancreatic cancers are adenocarcinomas of pancreatic duct epithelial cells; about 70% occur in the head of the pancreas, 20% in the body and tail, and the remaining 10% are numerous small tumors scattered throughout the pancreas. Pancreatic cancer is among the most malignant cancers. Because the pancreas is located deep within the abdominal cavity, its symptoms are difficult to detect, and most patients are diagnosed at an advanced stage. Furthermore, pancreatic cancer has a significant tendency to spread early, and traditional chemotherapy and radiotherapy are not very effective, resulting in a poor overall prognosis for pancreatic cancer.

According to the latest data from the Hong Kong Cancer Registry, there were 855 new cases of pancreatic cancer in Hong Kong in 2018, of which 475 were male and 380 were female. Most patients were 65 years of age or older. The total number of deaths was 711, making it the fifth leading cause of cancer death in Hong Kong.

iI. Classification of pancreatic cancer

Exocrine tumors

It usually originates in the inner wall of the pancreatic duct and is caused by uncontrolled proliferation of the glandular cells that secrete pancreatic juice. About 90% of pancreatic cancer cases belong to this category.

Endocrine tumors

This is caused by the uncontrolled proliferation of pancreatic glandular cells that secrete insulin, and accounts for less than 10% of all pancreatic cancer cases.

Causes of pancreatic cancer

To date, the medical community has not yet determined the exact cause of pancreatic cancer, nor can it definitively identify high-risk groups, as it does not appear to have a significant relationship with genetics, gender, or dietary habits. Furthermore, the link between chronic pancreatitis and pancreatic cancer is not actually established; however, these patients are often examined for chronic pancreatitis, and tumors are discovered during these examinations.

Ideally, like with other cancers, high-risk groups should be tracked and scheduled for regular checkups in hopes of identifying early-stage patients without symptoms as soon as possible. Data from the General Hospital Administration and the American Cancer Society show that pancreatic cancer is more common in people over 45, and most cases meet the following risk factors:

Common causes

Chronic pancreatitis
Diabetes mellitus
People infected with Helicobacter pylori have twice the risk of developing pancreatic cancer compared to those who are not infected.
Family history of pancreatic cancer
Relevant family history of genetic diseases, including BRCA gene mutations and Lynch syndrome.
As we age, especially after 45
Smoking: The risk of developing pancreatic cancer is at least twice that of the general population, and approximately 20% to 30% of pancreatic cancers are believed to be caused by smoking.
Obesity: Studies show that obesity increases the risk of pancreatic cancer. In the UK, approximately 10% of pancreatic cancer cases are related to being overweight.
Unhealthy eating habits, such as consuming large amounts of red meat and processed meats
Excessive alcohol consumption: Drinking alcohol can lead to chronic pancreatitis, and about 70% of chronic pancreatitis cases are caused by long-term heavy drinking. Chronic pancreatitis is one of the risk factors for pancreatic cancer.

Clinical symptoms of pancreatic cancer

Early symptoms of pancreatic cancer are difficult to detect. As the tumor grows, symptoms such as upper abdominal pain, back pain, jaundice, and weight loss will gradually appear. Generally speaking, the symptoms of pancreatic cancer vary depending on the location of the tumor in the pancreas.

Pancreatic cancer that forms in the head of the pancreas usually causes jaundice. The patient's skin and sclera will turn yellow, urine will be tea-colored, and stool will become lighter in color. At the same time, the skin may be itchy, and even symptoms such as fever and chills may occur.
Pancreatic cancer that develops in the body and tail of the pancreas typically causes upper abdominal and back pain. Because the cancer cells invade the nerve plexus in the upper abdomen, patients often experience persistent upper abdominal pain, which can only be relieved by leaning forward. The pain worsens when the body lies flat; this is a typical symptom. Sometimes, the pain is more intense after eating, and even light pressure on the abdomen can cause pain.
Some patients may experience abdominal bloating, nausea, or loss of appetite. This is because cancer cells obstruct the main pancreatic duct, reducing pancreatic juice secretion, causing indigestion, and hindering the body's absorption of nutrients, leading to weight loss.
In addition, when a tumor invades the transverse mesocolon, it can cause the colon to swell due to impaired peristalsis, which can exacerbate abdominal distension and vomiting. At this time, the tumor grows rapidly and consumes more nutrients, leading to a sudden drop in the patient's weight.

iII. Diagnosis of pancreatic cancer

The pancreas is located in the retroperitoneal region and is obscured by organs such as the stomach, so it may not be visible on a standard abdominal ultrasound. Blood tests measuring cancer markers also have limited sensitivity and accuracy—cancer markers are influenced by many factors and can produce false positives or false negatives, so they should only be used as a reference. Accurate diagnosis of pancreatic cancer requires a series of specialized examinations, among which the most important include:

Blood test (mainly to check for cancer markers CA19-9 or CEA)

The test checks for certain proteins in the blood that may be associated with pancreatic cancer. However, there is a possibility of a high level of these proteins without actual cancer (false positive) or a normal level of these proteins but with cancer (false negative). Therefore, it is not used as the sole basis for diagnosis, but rather as one of the reference values to determine whether further testing is needed.

Imaging examination

1. Enhanced computer scanning

Because the blood vessels of tumors differ from those of normal tissue, a contrast agent can be injected into the blood vessels first. After the contrast agent circulates through the bloodstream to the pancreas, abnormal blood flow can be observed through computer scanning to determine if there are cancer cells in the pancreas.

2. Magnetic Resonance

Scanning the bile duct and pancreatic duct to observe their structure and condition, such as whether there are any obstructions, signs of tumors, and the condition of tumor tissue, is roughly as detailed as the results of a CT scan.

3. Positron scanning

First, radioactive glucose is injected into the bloodstream. Because cancer cells have a higher metabolic rate than normal cells, they absorb more glucose, causing the radioactive glucose to accumulate in areas with a large number of cancer cells. Then, by scanning and detecting areas with high concentrations of radioactive elements, it can be determined whether there are cancer cells in the pancreas.

Tissue extraction: Endoscopic ultrasound

This procedure is often used when a patient has undergone multiple examinations and a pancreatic tumor is suspected, but its malignancy cannot be determined. Since a large part of the pancreas is close to the stomach, an endoscope can be inserted into the stomach first, and then ultrasound can be performed on the pancreas through the stomach wall. This allows for a clearer view of the pancreas, and a fine-needle aspiration (FNA) can be performed to extract tumor cell tissue for testing.

iV. Clinical staging of pancreatic cancer

The American Joint Committee on Cancer (AJCC) eighth edition staging system classifies pancreatic cancer into stages 0 to IV based on TNM status, with stage IV further subdivided into IVA and IVB.

T (tumor): refers to the size of the tumor and its spread to surrounding tissues.
N (lymph nodes): Indicates the extent and degree of tumor spread to regional lymph nodes.
M (metastasis): Indicates whether the tumor has spread to distant organs, such as bones and lungs.

Issue 1

This is early-stage pancreatic cancer; the tumor has just formed and is not large. Because the cancer cells are confined to the pancreas, radical surgical removal is possible.

Issue 1

Cancer cells have invaded the lymph nodes, duodenum, and bile ducts surrounding the pancreas, but have not yet invaded blood vessels, and can generally be removed surgically.

Issue 2

Tumors that occur in ependymal cells account for about 2% to 3% of all primary brain tumors.

Issue 3

Cancer cells may have spread to organs surrounding the pancreas, such as the stomach, spleen, and large intestine, and there may be local lymph node metastasis, but no distant organ metastasis.

Issue 4

The cancer cells have metastasized to distant organs, such as the lungs, liver, and abdominal lining.

V. Treatment methods for pancreatic cancer

Doctors will develop the most suitable treatment plan based on the patient's age, health condition, and factors such as the size, number, and location of the tumor. The main treatment methods for pancreatic cancer include surgery, chemotherapy, radiation therapy, and targeted therapy.

Surgery

Surgery is the only treatment that offers a chance of curing pancreatic cancer, but only about 15% of patients have the opportunity to have the tumor removed surgically in time.

Pancreaticoduodenectomy

This procedure is suitable for early-stage pancreatic head tumors and is currently the only surgery that can completely cure pancreatic cancer. The surgeon makes an incision in the patient's upper abdomen, removing the pancreas associated with the tumor, the gallbladder, the duodenum surrounding the pancreatic head, the pylorus (the lower end of the stomach connecting to the duodenum), and the lymph nodes around the pancreatic head. The remaining portion of the pancreas, along with the bile duct and the opening at the lower end of the stomach, is sutured to the small intestine, allowing pancreatic juice, bile, and processed food from the stomach to flow into the small intestine.

This surgery involves multiple internal organs and is quite lengthy, requiring patients to stay in the hospital for approximately ten days post-surgery. Initially, food may remain stuck in the patient's stomach and be unable to enter the small intestine, necessitating feeding via tube. Additionally, a small number of patients may experience leakage at the junction of the pancreas and small intestine, leading to abdominal inflammation. This requires drainage tubes to remove the blood clots, or antibiotics and tube feeding.

Pancreaticoduodenectomy with pylorus preservation

This procedure is suitable for early-stage pancreatic head tumors, preserving the pylorus of the stomach to allow food to enter the duodenum normally. Compared to pancreaticoduodenectomy, this surgery is shorter and involves less blood loss. Possible complications include gastric retention, leakage of pancreatic or bile, and abdominal infection.

Distal pancreatectomy

For tumors in the body or tail of the pancreas, the doctor will also remove the spleen and associated blood vessels. After spleen removal, the body's resistance decreases, and patients generally need to take antibiotics long-term. Common complications of this surgery include pancreatic leakage from the pancreatic incision or wound infection and inflammation.

Minimally invasive pancreatectomy

For early-stage tumors in the pancreatic tail, doctors make several small incisions in the abdominal wall, inject carbon dioxide to open the abdomen, insert a laparoscope, observe the condition of various organs on a screen, and then insert a scalpel to remove the tumor based on the images. This surgery is relatively minimally invasive, and patients can be discharged shortly after the operation. However, there is still a chance of problems such as pancreatic juice leakage and wound inflammation.

Total pancreatectomy

This procedure is suitable for patients whose cancer cells have spread throughout the entire pancreas. In addition to the entire pancreas, doctors will also remove the gallbladder, duodenum, pylorus (the lower end of the stomach), part of the bile duct, and surrounding lymph nodes. After surgery, because there is no longer pancreatic juice or insulin secretion, patients will need to use insulin supplements to control their blood sugar and take pancreatic enzyme supplements to aid digestion. Common complications of this surgery include pancreatic juice leakage from the pancreatic incision or wound infection and inflammation.

Postoperative care for pancreatic cancer:

Wound and drainage tube careAfter
After surgery, pancreatic cancer patients will have many medical tubes inserted into their bodies, requiring careful attention to prevent infection. During hospitalization, medical staff will provide timely aseptic protection for intravenous catheters and assess and determine the nature and number of drainage tubes used at each stage of recovery.
Nutritional
Nutritional support is typically provided via intravenous catheter within the first 24 hours after surgery. Five to seven days later, once the patient's gastric emptying function has recovered, oral feeding can gradually resume. Oral feeding should be introduced gradually, starting with liquids, then progressing to soft foods, and finally slowly returning to a normal diet.
After surgery
After surgery, patients are advised to practice deep breathing and coughing as much as possible to avoid infection problems caused by incomplete lung expansion in the early postoperative period. Twenty-four hours after surgery, if the patient's condition is stable and their strength allows, it is generally recommended to begin "gradual ambulation".
Blood sugar controlAfter
After partial pancreatic resection, insulin secretion decreases; if a total pancreatectomy is performed, the body loses its ability to secrete insulin, potentially leading to diabetes. Therefore, patients generally need to inject insulin after surgery until the pancreas recovers; patients who have undergone total pancreatectomy need to inject insulin daily.

Radiotherapy

High-energy radiation is used to irradiate cancer cells in a patient's body, damaging their chromosomes, interfering with their growth, and causing them to die. Radiation therapy can be performed externally or internally, but for pancreatic cancer, external beam radiation therapy is usually used. Radiation therapy may cause side effects such as fatigue, nausea, vomiting, and diarrhea, and the irradiated area may also experience skin redness and swelling. However, most of these side effects are temporary and will gradually subside after treatment.

Chemotherapy

Chemotherapy is a systemic treatment that typically involves dissolving chemotherapy drugs into the patient's bloodstream and circulating them throughout the body to attack rapidly growing cancer cells. However, while attacking cancer cells, other normal cells may also be damaged, so patients may experience side effects such as fatigue, nausea, loss of appetite, and hair loss after treatment.

Chemotherapy can be used to shrink tumors before surgery, or as adjuvant therapy after surgery to reduce the chance of recurrence. If the disease has progressed to an advanced stage, chemotherapy can also be used as palliative treatment to alleviate discomfort.

Commonly used chemotherapy drugs for pancreatic cancer include: gemcitabine, FOLFIRINOX (a combination of leucovorin, 5-fluorouracil, irinotecan, and oxaliplatin), nab-paclitaxel, and fluorouracil (5-FU). The number of treatment cycles depends on the stage of the disease and the patient's response to treatment, and the course of treatment generally lasts for 6 months.

Targeted therapy

Targeting cancer cells, including gene mutations, pathways or mechanisms of proliferation or spread, chemotherapy drugs directly block these targets that stimulate cancer cell growth, thereby inhibiting the growth and repair capabilities of cancer cells. This approach is more targeted than chemotherapy. In the treatment of pancreatic cancer, targeted therapy is often used in conjunction with chemotherapy.

Currently, most targeted drugs for pancreatic cancer are still in the clinical trial stage.

Palliative care

If the cancer has spread widely, the primary goal is to alleviate symptoms and maintain the patient's quality of life.

Shunting surgery

If a tumor obstructs the bile duct, doctors can place a stent inside the bile duct to keep it open. If there is intestinal obstruction, drainage surgery may be necessary.

Pain control

When a tumor presses on a surrounding nerve, it can cause severe pain, in which case a doctor may prescribe morphine-like painkillers. However, if medication is insufficient to relieve the pain, the doctor may discuss other options with the patient, such as using medication to block the transmission of pain signals from the nerve, or injecting alcohol into the nerve to sever the pain-sensing nerve.