Cancer Type

Stomach Cancer and its Examination Items Introduction

Stomach cancer is actually a very complex cancer, with different causes and staging characteristics. The following will detail relevant information about stomach cancer, including its causes and staging, examination items, treatment methods and costs, to help you fully understand stomach cancer, detect it early, and take appropriate treatment measures.

Introduction to Stomach Cancer

The stomach is part of the digestive system, located in the upper left abdomen below the ribs, connected to the esophagus above and the duodenum below. It is an organ for storing and digesting food.

Stomach cancer is a malignant tumor that grows in the stomach. It occurs when stomach wall cells divide and grow uncontrollably. According to the latest data from the Hong Kong Cancer Registry, stomach cancer ranks sixth among the top ten most common cancers in Hong Kong, with 1,277 new cases reported in 2018. Of these, 739 were in men and 538 in women, with a median age of 68 to 70 years.

Stomach cancer develops very slowly and can even remain dormant for years. Before it develops into true cancer, precancerous lesions may have already formed in the stomach lining. These early lesions rarely cause symptoms and are therefore difficult to detect. Therefore, regular stomach cancer screenings are especially important.

I. Classification of Gastric Cancer

Stomach cancer is classified into several types:

Adenocarcinoma

It accounts for 90% to 95% of gastric cancers and is the most common type of gastric cancer. Most gastric cancers are adenocarcinomas that occur in the mucosal epithelial layer.

Lymphoma

Tumors belonging to the immune system are sometimes found on the stomach wall, accounting for about 4% of all stomach cancers. The prognosis and treatment depend on the growth of the lymphoma.

Gastrointestinal stromal tumor（Gastrointestinal Stromal Tumor）

It is a rare type of tumor that originates from stromal cells in the stomach wall; some are benign, and some are malignant. Although this type of tumor can occur anywhere in the digestive tract, 60% to 70% occur in the stomach.

Carcinoid Tumor

Tumors belonging to neuroendocrine cells account for approximately 3% of all gastric cancers.

Causes of stomach cancer

To date, the medical community has not yet determined the exact cause of stomach cancer, but certain factors are known to increase the risk of developing it, including:

Gender：The incidence of gastric cancer in men is higher than that of women.

Age：Gastric cancer is more common in the elderly, and most patients are over 50 years old.

Family inheritance：An immediate family member has suffered from stomach cancer or esophageal cancer.

Helicobacter pylori infection:Long-term infection with Helicobacter pylori can lead to inflammation of the gastric mucosa (chronic atrophic gastritis) and precancerous lesions of the mucosa. Individuals infected with Helicobacter pylori have a higher incidence of stomach cancer if left untreated.

Pernicious anemia: This type of anemia:is caused by gastric mucosal atrophy and a lack of intrinsic factor in gastric juice, which leads to impaired absorption of vitamin B12. Patients with pernicious anemia have a higher risk of gastric cancer.

Chronic gastrointestinal disease:such as long-term atrophic gastritis, gastric ulcers, and acid reflux can all potentially develop into stomach cancer.

Adenomatous polyps:Polyps are quite common in the digestive system, and most are benign. However, some larger adenomatous polyps (greater than 2 cm) have the potential to become cancerous.

Other factors include:poor diet and lifestyle habits, such as consuming large amounts of smoked, pickled, and grilled foods, smoking, excessive alcohol consumption, lack of exercise, and obesity.

If you have any of the above high-risk factors, it is recommended that you undergo regular individual examinations for stomach cancer in order to detect problems as early as possible.

II. Classification and Examination Items of Gastric Cancer

If you seek medical attention due to suspected stomach cancer, your doctor will typically ask about your personal and family medical history, as well as some questions related to stomach cancer risk factors. They will also inquire about your symptoms and overall health, and conduct a preliminary assessment of your abdomen through a clinical abdominal examination to rule out any abnormalities. Further stomach cancer screenings include:

Upper gastrointestinal endoscopy (OGD)

This procedure, commonly known as a "gastroscopy," is used to examine the esophagus, stomach, and duodenum, and is a common diagnostic method for stomach cancer. The doctor will spray an anesthetic into the back of the patient's throat, and if necessary, inject a small amount of sedative into a vein in the arm. Then, a flexible tube with a light source and lens at the tip is inserted through the esophagus into the stomach and duodenum. The stomach wall, as well as surrounding lymph nodes and organs, are observed on a screen for any abnormalities. During the examination, if suspicious abnormal tissue is found, the doctor will perform a tissue biopsy, extracting a small amount of tissue for pathological examination to determine if cancer cells are present. If the tissue biopsy confirms the presence of cancer cells, further stomach cancer screenings will be required.

Endoscopic ultrasound (EUS)

Similar to gastrointestinal endoscopy, EUS is equipped with an ultrasound probe, which has higher resolution and can penetrate deep into the body to examine lesions, thus enabling accurate diagnosis and staging.

Imaging examination

These imaging modalities are used to determine the size, number, location, spread, and distribution of tumors in order to decide on a treatment plan. These imaging modalities include computed tomography (CT scan), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT).

Laboratory tests

Blood tests are used to check for anemia and to assess liver and kidney function, providing valuable information for developing a treatment plan.

Staging of gastric cancer

The staging of gastric cancer is crucial for developing a treatment plan. The commonly used staging system is the TNM system, which divides gastric cancer into stages 0 to 4.

Issue 0

Abnormal cells are present in the lining of the stomach. This stage is high-grade dysplasia, also known as "carcinoma in situ." This stage is rare, and the risk of gastric cancer cell spread is very low.

Issue 1

This generally refers to stomach cancer cells that have not spread to the stomach wall muscle layer, other parts of the body, or distant organs. It can be further subdivided into:

Stage Ia:Cancer cells have not invaded the submucosa.

Stage Ib:Cancer cells have not invaded the muscle layer, but may have spread to one or two adjacent lymph nodes.

Issue 2

This generally refers to gastric cancer cells spreading to the mucosa, submucosa, or muscle layer; it may also spread to the outer wall of the stomach and adjacent lymph nodes, but not to other parts of the body or distant organs. It can be further subdivided into:

Stage IIa:Cancer cells invade the mucosa, submucosa, or muscle layer; and spread to adjacent lymph nodes, but not to distant organs.

Stage IIb:Cancer cells invade the mucosa, submucosa, muscularis propria, or outer wall of the stomach; and spread to adjacent lymph nodes; or cancer cells spread to the outer wall of the stomach but not to adjacent lymph nodes.

Neither of them spread to other parts of the body or distant organs.

Issue 3

This generally refers to gastric cancer cells spreading to the mucosa, submucosa, muscle layer, or outer wall of the stomach; it may also spread to nearby lymph nodes, but not to other parts of the body or distant organs. It can be further subdivided into:

Stage IIIa:

Cancer cells invade the muscle layer or the outer wall of the stomach and spread to nearby lymph nodes; or cancer cells invade the stomach wall, adjacent organs or tissues, but have not spread to the lymph nodes. In both cases, the cancer has not spread to distant organs.

Stage IIIb:

Cancer cells have invaded the mucosal layer, submucosal layer, muscular layer, or the outer wall of the stomach; or cancer cells have invaded the outer wall of the stomach and adjacent organs or tissues. In both cases, the cancer has spread to the lymph nodes but has not metastasized to distant organs.

Stage IIIc:Cancer cells have invaded the outer wall of the stomach, or the outer wall of the stomach, as well as adjacent organs or tissues. Both have spread to the lymph nodes, but not to distant organs.

Issue 4

This generally refers to the late stage of gastric cancer, where gastric cancer cells have spread to the outer wall of the stomach, adjacent organs or tissues, or to distant organs. It can be further subdivided into:

Stage IVa:Cancer cells have invaded the outer wall of the stomach, adjacent organs or tissues; they may have spread to nearby lymph nodes, but not to distant organs.

Stage IVb:Cancer cells have spread to distant organs.

Small cell lung cancer accounts for about 15% of all lung cancer cases, and the majority are caused by smoking. This type of lung cancer generally grows faster than non-small cell lung cancer, and about 70% of patients have already experienced metastasis at the time of diagnosis.

III. Treatment of Gastric 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 stomach cancer include:

Surgical procedures:Partial or total gastrectomy is the most effective radical treatment for early-stage gastric cancer.

Adjunctive therapy：Radiotherapy or chemotherapy may be administered before or after surgery to enhance the therapeutic effect.

Palliative care:If cancer cells have spread, radiation therapy or chemotherapy drugs can be used to control the disease and alleviate symptoms.

Targeted therapy:Only suitable for HER2 receptor-positive gastric cancer, and must be used in combination with chemotherapy.

Immunotherapy:Suitable for gastric cancer patients with high PD-L1 protein expression in their tumors or those exhibiting defects in gene mismatch repair (MMR).

Surgery

Surgical intervention is the primary treatment for stomach cancer. For patients with early-stage stomach cancer, removing most or all of the stomach, along with adjacent lymphatic tissue, is the most effective radical treatment and is also one of the more expensive stomach cancer treatments in the local private healthcare system. After stomach removal, the doctor will connect the small intestine to the esophagus, allowing the patient to continue eating after surgery. Depending on the size and location of the tumor, sometimes the entire stomach may need to be removed, known as a "total gastrectomy," and even parts of the esophagus, pancreas, and greater omentum may need to be removed. If the cancer cells have spread, radical resection is not suitable, and palliative surgery may be considered to improve the obstruction of the stomach outlet. Some patients require postoperative radiation therapy or drug therapy to consolidate the treatment effect.

Minimally invasive laparoscopic gastrectomy:
The doctor inserts a laparoscope through a small incision in the abdomen into the stomach. By observing the images on a screen, they make a small incision in the abdomen and insert a scalpel to remove the tumor. The incision is only about one inch wide. Minimally invasive laparoscopic gastrectomy is less traumatic, allows for faster patient recovery, and has fewer complications.

Endoscopic resection:

For very early-stage gastric cancer where cancer cells have only invaded the mucosal layer, the chance of cancer cells spreading to the lymph nodes is very low. Generally, it is only necessary to insert an endoscope through the throat into the stomach and then directly remove the tumor without making an abdominal incision. However, not all early-stage gastric cancers are suitable for this surgery. If the tumor has invaded the submucosal layer, the cancer cells are highly malignant, or the patient has coagulation problems, then endoscopic resection is not suitable.

Endoluminal stent placement

If a tumor blocks the cardia (the entrance to the stomach) and pylorus (the exit to the stomach), the tumor may be difficult to remove. However, to facilitate eating, a stent may be placed to allow food to pass through, thus maintaining the patient's quality of life as much as possible. Under X-ray guidance, the doctor will insert an endoscope and place the stent through the esophagus to the tumor site, opening and clearing the obstruction. In addition to stent placement, a "bypass" technique may also be used, connecting the stomach above the obstruction to the duodenum, bypassing the obstruction and reopening the passage for food.

Lymph node removal

Nearby lymph nodes are prone to spreading. In addition to lymph nodes, the stomach is surrounded by blood vessels responsible for supplying nutrients, further increasing the risk of spread. Before surgery, doctors will conduct a health assessment and, if feasible, perform surgery to remove the gastric blood vessels and lymph nodes.

Insert a feeding tube.
After gastric tumor removal, patients generally need to undergo chemotherapy or radiation therapy to reduce the chance of recurrence. To help patients recover their strength as soon as possible for postoperative adjuvant therapy, doctors may insert a feeding tube into the small intestine during tumor removal to provide fluid nutrition during the recovery period.

Headache:The headache is usually a dull ache; coughing, sneezing, and using the toilet can worsen it. Early headaches typically only occur upon waking in the morning; in later stages, the headaches become persistent and increasingly severe, and medication often fails to alleviate them.

Vomiting:Vomiting caused by brain cancer often comes on suddenly and violently, like "projectile vomiting," and is not necessarily accompanied by headache and nausea beforehand.

Visual impairment:Patients may experience blurred vision and double vision.

Impaired consciousness:This is caused by reduced blood flow to the brain and impaired brainstem function. If a brain tumor grows rapidly, it can cause cerebral edema, and the patient may go from being fully conscious to being in a coma in a short period of time.

Postoperative precautions

The stomach is an important digestive organ. After gastrectomy, the digestive rate may slow down, and the stomach's capacity will decrease. Therefore, patients need to make some adjustments to their diet, such as eating smaller, more frequent meals, avoiding overeating, and eating easily digestible foods to reduce the burden on the digestive system. On the other hand, to recover properly from surgery, the body needs to ingest sufficient nutrients. If it is found that the patient has not returned to a proper diet after surgery, the doctor may recommend that the patient take nutritional supplements. In addition, after the stomach is removed, the body's ability to absorb iron and vitamin B12 is weakened, which can easily lead to anemia. Doctors may administer vitamin B12 injections or prescribe iron and calcium supplements.

Radiotherapy

External beam radiation therapy (EMB) uses high-energy radiation to penetrate the body and reach specific locations to destroy cancer cells. For stomach cancer, ERB is typically used, and its effects include:

Shrinking tumors and improving gastrointestinal obstruction
Relieve pain caused by tumor
Controlling gastric tumors that cause bleeding

Radiation therapy may cause side effects such as fatigue, nausea, vomiting, and diarrhea. The skin at the irradiated site may also become red, swollen, and peel. Most side effects can be relieved with prescription medication, and most are temporary, gradually subsiding after treatment.

Chemotherapy

Traditional chemotherapy

Traditional chemotherapy is a treatment method that kills cancer cells through drugs. It is a systemic (i.e., whole-body) treatment, generally administered intravenously or orally. Traditional chemotherapy is typically used in the following situations:

Adjuvant chemotherapy is administered after gastrectomy to reduce the chance of cancer recurrence, and may sometimes be combined with radiation therapy.
When stomach cancer metastasizes, such as to the liver or abdominal cavity, doctors will use chemotherapy to control the disease and relieve symptoms.
In some cases, doctors may recommend that patients undergo chemotherapy before gastric removal surgery to shrink the tumor and increase the chances of a successful operation.

Commonly used chemotherapy drugs for treating stomach cancer include 5-fluorouracil, capecitabine, cisplatinum, epirubicin, oxaliplatin, TS1, and docetaxel. Doctors may consider combining two or three chemotherapy drugs depending on the patient's condition and overall health.

Side effects of chemotherapy vary from person to person, and common ones include nausea, hair loss, mouth ulcers, and rashes. Patients do not need to worry excessively. The most important thing is to maintain a positive attitude and communicate openly with their doctor. Doctors can help alleviate the side effects of chemotherapy through various methods.

Intraperitoneal chemotherapy

In traditional systemic chemotherapy, the drugs are first distributed throughout the body via the bloodstream, with only a small portion reaching the abdominal cavity to act on the tumor. Intraperitoneal chemotherapy, as the name suggests, involves directly infusing chemotherapy drugs into the peritoneal cavity to achieve a localized tumor-killing effect.

There are three types of intraperitoneal chemotherapy:

Intraperitoneal high temperature chemotherapy
Intraperitoneal chemotherapy at room temperature
Gasification intraperitoneal chemotherapy

Intraperitoneal high temperature chemotherapy (hyperthermic intraperitoneal chemotherapy, HIPEC)

This procedure is performed after gastrectomy. Doctors will inject chemotherapy drugs heated to 41 to 42 degrees Celsius into the abdominal cavity through a catheter. After circulating for about an hour and a half, digestive tract reconstruction surgery will be performed to complete the procedure.

Intraperitoneal chemotherapy at room temperature (catheteraperitoneal chemotherapy, CIPEC)Another option involves surgery to insert a subcutaneous peritoneal tube into the abdomen, allowing oncologists to inject chemotherapy drugs into the abdominal cavity during the third week of systemic chemotherapy, which is administered every six weeks, so that the drugs can be absorbed on their own.

Gasification intraperitoneal aerosol chemotherapy (pressured intraperitoneal aerosol chemotherapy, PIPAC)PIPAC uses carbon dioxide to atomize chemotherapy drugs and then sprays them throughout the patient's abdominal cavity. PIPAC requires a lower dose of drugs than systemic chemotherapy and has less toxicity to the liver, kidneys, and gastrointestinal tract.

The latest trend is to combine traditional chemotherapy with intraperitoneal chemotherapy, a practice known as"bidirectional treatment".

Intraperitoneal chemotherapy is not only used for stomach cancer but also for other diseases where cancer cells have spread to the abdominal cavity, including the most common colorectal cancer, pancreatic cancer, ovarian cancer, and cervical cancer. These diseases share the common characteristic of persistent ascites caused by cancer cells. Traditional treatments simply involve repeated drainage, but intraperitoneal chemotherapy helps prevent ascites recurrence and alleviates patient suffering. Because intraperitoneal chemotherapy directly targets cancer cells, it requires a smaller dose of drugs with higher efficacy and relatively fewer side effects.

Intraperitoneal chemotherapy is performed in the operating room, where doctors will make two to three incisions, each about the size of a thumb, in the patient's abdomen. The procedure takes about an hour. As long as the patient's cardiopulmonary function is good, the surgical risk is quite low, and the patient can usually be discharged home within one to two days. However, this surgery also has its limitations; if the abdominal tumor is large and adheres to the abdominal wall, this treatment method is not suitable.

Targeted therapy

Strictly speaking, targeted therapy is a type of chemotherapy. Currently, there are two types of drugs used for targeted therapy of gastric cancer:

The first type is Ramucirumab, which is a monoclonal antibody that antagonizes vascular endothelial growth factor receptor type 2 (VEGFR2). It can be used alone or in combination with chemotherapy drugs and is the standard treatment for metastatic gastric cancer.

Another option is Trastuzumab, whichis suitable for patients with metastatic gastric cancer whose tumors are confirmed to be HER2 receptor-positive. Therefore, doctors will perform HER2 receptor testing on the gastric cancer tissue. Trastuzumab must be used in combination with chemotherapy drugs.

Generally speaking, targeted therapies have milder side effects and cause fewer additional side effects to patients, but they are more expensive than conventional chemotherapy for stomach cancer.

Immunotherapy

Immunotherapy differs from traditional cancer treatment concepts; it does not directly attack tumors but rather fights cancer cells by activating the patient's own immune function. Currently, the main immunotherapy drugs used for gastric cancer are "immune checkpoint inhibitors," but they are only suitable for a very small percentage of gastric cancer patients whose tumors have high PD-L1 protein expression or exhibit gene mismatch repair deficiency (dMMR).

Cost of stomach cancer treatment

As can be seen from the above, there are many different treatment options for stomach cancer, making it difficult to give a precise cost estimate. Chemotherapy can be as low as a little over HK$1,000, while complex surgery can cost over HK$200,000. If needed, you can consult the professional team at HKUOC to learn about the latest stomach cancer treatment methods and costs.

FAQ

1. What is stomach cancer?

Stomach cancer is a malignant tumor that grows in the stomach. When the cells of the stomach parietal wall divide uncontrollably, they may form various types of cancer, such as adenocarcinoma, lymphoma, gastrointestinal stromal tumor, or carcinoid. Common causes include genetics, Helicobacter pylori infection, and dietary habits.

2. How is stomach cancer staged?

Stomach cancer is classified into stages 0 to 4 according to the TNM system. Stage 0 cancer cells are confined to the epithelium, while stage 4 indicates that the cancer cells have spread to other organs.

3. What are the main treatment methods for stomach cancer?

Treatment options include surgical resection, adjuvant chemotherapy, targeted therapy, and immunotherapy, with specific plans determined by doctors based on the patient's condition.

4. What are the common tests for stomach cancer? How much do they cost?

Diagnostic tests for stomach cancer include upper gastrointestinal endoscopy (gastroscopy), endoscopic ultrasound, imaging studies (such as CT, MRI, PET-CT), and blood tests. These tests help doctors determine the size, location, and whether the tumor has spread.

The cost of stomach cancer screening varies depending on the tests performed and the location. A typical gastroscopy costs several thousand Hong Kong dollars, while imaging examinations such as CT, MRI, and PET-CT can cost anywhere from several thousand to tens of thousands of dollars per test. It is recommended to consult a medical institution for detailed pricing information.

5. How much does stomach cancer treatment typically cost?

The cost of stomach cancer treatment depends on the treatment method, such as surgery, radiation therapy, chemotherapy, targeted therapy, or immunotherapy. Costs range from several thousand to hundreds of thousands of Hong Kong dollars, with some targeted or immunotherapy drugs being more expensive. Patients can contact us for specific costs and financial assistance options.