Stomach Cancer: Symptoms, Causes, and Treatment

08 July,2024

Have you ever eaten a delicious meal only to feel discomfort afterward? That persistent heartburn might be more than just indigestion. Today, we'll explore stomach cancer, a serious but treatable illness.

Picture your stomach, the hardworking organ that breaks down everything from juicy steaks to crunchy salads. Now, imagine a disruption in its normal functioning – abnormal cells start multiplying, forming tumors, and disturbing the smooth digestive process. That's stomach cancer in a nutshell.

But don't worry! This isn't a horror story. We can empower ourselves by understanding the risks, symptoms, and available treatments. Get ready because we're about to learn more about stomach cancer and how to conquer this potentially fatal disease!

What is Stomach Cancer?

Before we learn about stomach cancer, let's understand the organ itself. The stomach is a pouch-like organ that plays a vital role in digesting food. It comprises five parts: cardia, fundus, body, antrum, and pylorus. The wall of the stomach has five layers: mucosa, submucosa, muscularis propria, subserosa, and serosa. The extent or stage of stomach cancer is defined by the layers involved.

Stomach or gastric cancer is marked by abnormal growth of cells in the stomach wall. Cells from any layer of the wall can go haywire and form tumors. Over 1 million people are diagnosed with stomach cancer annually, and it has become the 5th most frequent cancer among people.

The type of stomach cancer depends on the type of cells it begins from. It can be classified as –

• Adenocarcinomas: Adenocarcinoma stomach cancer accounts for 90 to 95% of stomach cancer cases. It starts from the cells that produce mucus.
• Gastrointestinal Stromal Tumors (GIST): GIST is a soft tissue sarcoma originating in specialized nerve cells in the stomach and other digestive organs.
• Carcinoid Tumors: Stomach cancers that start in the neuroendocrine cells are known as carcinoid tumors. Neuroendocrine cells perform nerve cell functions.
• Lymphoma: Gastric lymphoma is a type of stomach cancer originating from the stomach's lymphatic tissues. It generally accounts for 5% of all stomach cancer cases.

An oncologist is a highly skilled and specialized medical professional who diagnoses and treats stomach cancer.

What are the Causes and Risk Factors of Stomach Cancer?

Stomach cancer happens when the cells in the stomach wall start dividing uncontrollably. Exactly why this happens is still not known. However, several risk factors have been associated with it. These include –

• Helicobacter Pylori Infection: Chronic infection with H. pylori, a gram-negative bacterium, is the most potent known risk factor for gastric cancer. The infection triggers chronic inflammation of the gastric mucosa, leading to gastritis and, ultimately, to stomach cancer.
• Genetic Predisposition: Having a first-degree relative with gastric cancer modestly increases an individual's risk. Specific hereditary syndromes like Lynch syndrome (hereditary non-polyposis colorectal cancer) and Li-Fraumeni syndrome can also predispose individuals to stomach cancer.
• Dietary Factors: A diet high in red meats and salted fish and low in vegetables, fruits, and fiber is linked with an increased risk of gastric cancer. Nitrates and nitrites in processed meats are converted to carcinogenic N-nitroso compounds in the stomach. Conversely, a diet rich in vegetables and fruits may offer a protective effect due to the presence of antioxidants and fiber.
• Gender and Age: Men are more likely to develop stomach cancer than women. Moreover, people aged 50 and above are at a higher risk of the disease. American Cancer Society states over 60% of people diagnosed with gastric cancer are aged 65 or above.
• Certain Gastric Conditions: Gastrointestinal disorders such as peptic ulcers and stomach polyps can also develop into stomach cancer over a period of time.
• Tobacco Smoking: Cigarette smoking is a well-established risk factor for gastric cancer. Smoking directly damages the gastric epithelium and promotes chronic inflammation, creating a conducive environment for carcinogenesis.
• Obesity: Extra body weight increases the risk of stomach cancer in the cardia region. The mechanisms underlying this relationship are not fully known but may involve hormonal and metabolic alterations.

People with one or more of these risk factors should consider getting a check-up at an advanced oncology hospital.

What are the Symptoms of Stomach Cancer?

Symptoms of stomach cancer can be pretty vague initially. That's why it isn't easy to diagnose in the early stages. The symptoms might also depict other gastrointestinal conditions, such as stomach ulcers.

Early symptoms of stomach cancer are –

• Bloating
• Heartburn
• Indigestion
• Stomachache
• Vomiting
• Swallowing difficulties
• Burping

As the cancer disease progresses to advanced stages, the symptoms become more severe and concerning. These include –

• Black stool
• Fluid buildup in the stomach
• Anemia
• Loss of appetite
• Unexplained weight loss
• Fatigue

Although these symptoms can be similar to those of other stomach diseases, people who are at an increased risk of developing stomachs must not ignore them. Symptoms such as difficulty swallowing and blood in stool or vomit warrant an immediate consultation with gastroenterologists.

How is Stomach Cancer Diagnosed?

To diagnose stomach cancer, the oncologist will ask about the symptoms you are experiencing and their severity. They will conduct physical examinations and take your medical and family history. The doctor will then order several tests to make a confirmed diagnosis of the cancer. These tests include –

• Endoscopy: This minimally invasive procedure involves inserting an endoscope (thin, flexible tube with a camera) down your throat and into your stomach. The doctor can then visualize the stomach lining directly, searching for abnormalities like ulcers or tumors. During an endoscopy, tissue samples (biopsies) can be collected for further analysis.
• Biopsy: This is the gold standard for assessing cancer. Tiny tissue samples are extracted from suspicious areas during an endoscopy or other procedures. A pathologist then examines these samples under a microscope to identify the existence or absence of cancer cells. It also helps in staging the stomach cancer.
• Ultrasound: Ultrasound can help determine the stage and spread of stomach cancer. It uses sound waves to capture photos of your internal organs. Ultrasound can assess the thickness of the stomach wall and detect any enlarged lymph nodes near the stomach, which might indicate cancer spread.
• Laparoscopy: Similar to endoscopy, laparoscopy also uses a thin tube with a camera to visualize internal organs. However, the endoscope is inserted through a small abdominal incision. This minimally invasive surgery provides a broader view of the abdominal cavity, allowing doctors to examine the stomach and surrounding organs for signs of cancer spread.
• Radiological Imaging: An upper GI series (barium swallow) involves ingesting a chalky liquid that coats the digestive tract, allowing X-rays to visualize abnormalities in the stomach and esophagus. Computed tomography scans (CT scans) create detailed cross-sectional images of your abdomen and pelvis, giving doctors a clearer picture of the tumor and its potential spread to nearby organs. PET scans use radioactive tracers to identify areas of increased metabolic activity, which can indicate cancer cells.
• Blood Tests: While not diagnostic for cancer itself, blood tests can provide clues about your overall health and potentially reveal complications associated with stomach cancer, such as anemia or electrolyte imbalances. Some blood tests may also check for specific markers that can be elevated in some stomach cancers.

What are the Treatment Options for Stomach Cancer?

Stomach cancer treatment depends on multiple factors, such as the stage and type of cancer, if the cancer has spread to other body parts (metastasis), and your overall health.

A multidisciplinary team of doctors, such as gastroenterologists, medical oncologists, surgical oncologists, and radiation oncologists, will decide the best possible treatment plan for you.

Treatment options for stomach cancer include –

Surgery

Oncologists may use different types of surgeries depending on the stage of gastric cancer and its location in the part of the stomach. Standard surgical techniques for treating stomach cancer are:

• Endoscopic Resection: Early-stage cancers confined to the stomach lining and not grown deeper into walls can be removed with endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) procedures. These surgeries involve inserting an endoscope along with surgical tools into the stomach through the throat. It does not involve making any incisions in the skin.
• Partial Gastrectomy: Subtotal gastrectomy or partial gastrectomy is a procedure to remove parts of the stomach when the cancer is localized to a specific part of the organ. When the lower part of the stomach is removed, it is known as distal gastrectomy; if the upper stomach is removed, it is known as proximal gastrectomy. The surgeon may also remove other body parts, such as the esophagus, spleen, lymph nodes, and omentum, if they are affected by the cancer.
• Total Gastrectomy: When the cancer is widely spread in the stomach, complete removal of the organ is advised. The procedure is known as a total gastrectomy. The esophagus is directly attached to the small intestines, and patients undergoing total gastrectomy can only eat small amounts of food at once.

Chemotherapy

Chemotherapy is the use of cancer-killing cells. Doctors can give chemotherapy before surgery (neoadjuvant therapy) or after the surgery (adjuvant treatment). Types of chemotherapy for stomach cancer include:

• Systemic Chemotherapy: The chemo drugs are delivered orally or intravenously and travel throughout the body, killing cancer cells.
• Hyperthermic Intraperitoneal Chemotherapy (HIPEC): In HIPEC, the chemo drugs are directly put in the stomach. It is like washing the stomach with cancer-killing cells, after the surgery.

Radiation Therapy

High-energy beams of X-rays, protons, and other sources can also destroy tumors. This type of cancer treatment is known as radiation therapy. Oncologists can use radiation therapy before surgery to shrink or reduce tumor size. They can also give therapy after the surgery to kill any remaining cancer cells.

Intensity-modulated radiation therapy (IMRT) and 3D-CRT use computers to aim the radiation precisely at the tumor and deliver radiation from different angles. The treatment takes little time and can be completed within minutes.

Immunotherapy

Immunotherapy involves using medicines to boost immunity. It works by enhancing the ability of the immune system first to recognize and then fight cancer cells. 

Oncologists use immunotherapy to treat advanced cancers such as stage 4 stomach cancer. They can also use it for cancer that comes back after treatment.

Side effects of immunotherapy are fever, skin rash, cough, vomiting, nausea, shortness of breath, muscle pain, and loss of appetite.

Targeted Therapy

Targeted therapy is different from standard chemotherapy. Drugs used in targeted therapy attack specific chemicals and proteins in the cancer cells. These drugs can be used alone or in combination with chemotherapy.

Targeted therapy is not for everyone. Cancer specialists will check the cancer cells for the specific antigens to be present on the cancer cells and then decide if the drugs will work on them or not.  

Common drugs used for targeted therapy are trastuzumab, fam-trastuzumab deruxtecan, ramucirumab, larotrectinib, and entrectinib.

How Can You Prevent Stomach Cancer?

Preventing stomach cancer entirely is difficult. However, by taking a few proactive steps, you can reduce the chances of developing stomach cancer. These include –

• Manage H. Pylori Infection: If you test positive for H. pylori, your doctor will recommend antibiotics to eradicate the bacteria and potentially reduce your long-term risk of stomach cancer.
• Quit Smoking: Smoking is a risk factor for many cancers, including stomach cancer. Kicking the habit is one of the best things you can do for your overall health.
• Maintain a Healthy Weight: Being obese or overweight increases your risk of stomach cancer. Aim for a healthy weight by exercising regularly and eating a balanced diet.
• Eat Healthy: Aim for a colorful plate! Fill your meals with fruits and vegetables, especially those rich in vitamin C and beta-carotene, like oranges, leafy greens, and carrots. Replace refined grains for whole grains like brown rice, quinoa, and whole-wheat bread. Cut back on processed meats like bacon and go easy on salted foods like processed snacks.

What is the Survival Rate of Stomach Cancer?

The survival rate for stomach cancer varies significantly depending on its stage at diagnosis. Other factors influencing the chances of beating stomach cancer successfully and surviving for a good time are –

• Age and Overall Health: Younger patients and those in better general health tend to have better prognoses.
• Type of Cancer: Certain types of stomach cancer may have different survival rates.
• Treatment Response: How well the tumor responds to treatment is crucial to survival.

The outlook for stomach cancer improves dramatically with earlier detection. For localized cancer (confined to the stomach), the 5-year survival rate is up to 75%. Timely diagnosis of gastric cancer is essential for more effective treatment options and gives a higher chance of cure.

Survival rates decrease considerably for advanced stages. For regional cancer (spread to nearby lymph nodes), the 5-year survival rate is 35%.

Outlook

Stomach cancer, while a serious illness, is not without hope. Early detection is critical for successful treatment. If you're concerned about stomach cancer, schedule a checkup with your doctor, especially if you experience persistent symptoms. Don't hesitate to discuss your family history and any questions you might have. By staying informed, adopting healthy habits, and seeking medical advice when needed, you can take control of your health and fight stomach cancer effectively.