What is Stomach Cancer? What are Its Symptoms and Treatment?

Stomach cancer is a type of cancer that occurs due to the uncontrolled growth and multiplication of cells lining the surface of the stomach. It can form at the junction of the esophagus and stomach or in the body of the stomach. Compared to other cancers, it develops more slowly.

What is Stomach Cancer?

Stomach cancer is a condition characterized by malignant tumor formations that develop due to uncontrolled cell division within this organ. The stomach, a muscular sac, is located in the upper middle part of the abdomen, just below the ribs. It temporarily stores food consumed and is also responsible for the breakdown and digestion of various nutrients. Also known as gastric cancer, stomach cancer can develop in any part of this organ. The most common site of occurrence is the main part of the stomach, known as the body.

After stomach cancer is detected, the treatment planning first considers which part of the stomach the cancer is located. Treatment interventions generally aim to surgically remove the cancerous tissue, but other various treatment applications may be added in some cases.

What Causes Stomach Cancer?

The stomach, along with the esophagus, forms the upper part of the digestive system. This organ temporarily stores food consumed and then transfers the mixture of food to the small intestine. The basic mechanism of stomach cancer development is the transformation of normal healthy cells in this organ into tumors due to uncontrolled growth. This development usually occurs over many years.

Several factors can increase the risk of developing stomach cancer in an individual. Some of these factors can be generally summarized as follows:

• Bacterial infections characterized by the development of ulcers, known as Helicobacter pylori
• Tumor development in other parts of the digestive system
• Stomach polyps
• Hereditary syndromes such as Lynch or Li-Fraumeni

In addition to these conditions, risk groups where stomach cancer cases are more frequently detected are as follows:

• Individuals aged 60 and over
• Male gender
• Tobacco use
• Overweight or obese individuals
• Family history of stomach cancer

Apart from personal medical history, there are different conditions considered as risk factors for the development of stomach cancer:

• Consumption of excessively salty or processed food products
• Frequent eating
• Lack of fruit consumption
• Smoking
• Lack of adequate exercise
• Consumption of foods that have not been stored under proper conditions or cooked using correct methods

Since the risk of developing stomach cancer is increased in individuals with one or more of these factors, it is recommended to monitor these individuals for stomach cancer using various screening methods. Screening applications allow the disease to be detected at an early stage in at-risk individuals before any symptoms appear.

Types of Stomach Cancer

• Adenocarcinoma (accounts for 90% of cases)
• Lymphoma
• Gastrointestinal stromal tumor
• Carcinoid tumor (develops from hormone-secreting cells of the stomach)
• Squamous cell carcinoma
• Small cell carcinoma
• Leiomyosarcoma

Risk Factors for Stomach Cancer

Several risk factors that can lead to stomach cancer have been identified. Some of these risks are controllable while others are not. For example, smoking is a controllable risk factor, while genetics is not. The main causes of stomach cancer are:

• Stomach cancer is more common in men than in women.
• The risk of stomach cancer increases over the age of 50.
• Stomach cancer is more common in certain races.
• Stomach cancer is more frequently seen in Japan, China, South and Eastern Europe, and South and Central America.
• Helicobacter pylori infection: There is a relationship between this bacterial infection and stomach cancer. However, not everyone with H. pylori develops stomach cancer.
• Diet: People who consume a lot of smoked and cured foods, salted fish and meat, and pickled vegetables have a higher incidence of stomach cancer. Dried meats contain high amounts of nitrates. Consuming a lot of fruits and vegetables is protective against stomach cancer.
• Smoking: The risk of stomach cancer doubles in smokers, especially at the junction of the stomach and esophagus.
• There is an uncertain relationship between being overweight and stomach cancer.
• People who have previously undergone stomach surgery have a higher risk of developing stomach cancer.
• Stomach cancer is more common in people with pernicious anemia caused by vitamin B12 deficiency.
• For unknown reasons, stomach cancer is more frequently reported in people with blood type A.
• Having a family history of cancer.
• People who carry mutations in the hereditary breast cancer genes BRCA1 or BRCA2 may have a higher risk of stomach cancer.
• Stomach cancer is more common in patients with polyps in the stomach, intestines, nose, lungs, and bladder.
• Some cases of stomach cancer have a history of past EBV (Epstein-Barr virus) infection.
• Workers in the coal, metal, and rubber industries have a higher risk of developing stomach cancer.
• Patients with chronic atrophic gastritis may develop stomach cancer over time.

Mide Kanseri Belirtileri Nelerdir?

Mide kanseri belirtileri kişiden kişiye değişiklik gösterebilir. Bazı bireylerde mide kanseri gelişimi çok yavaş bir süreç olduğu için yıllar boyunca herhangi bir şikayet meydana gelmeyebilir.

Erken evre mide kanserlerinde, mide ülseri varlığında oluşan şikayetlere benzer belirti ve bulgular gelişebilir. Bu belirtiler genel olarak şu şekilde özetlenebilir:

• Öğünler sırasında erken doyma
• Yutma problemleri
• Öğün sonrası aşırı şişkinlik
• Sürekli geğirme isteği olması
• Mide yanması
• Geçmeyen hazımsızlık
• Mide ağrısı
• Göğüs kemiği üzerinde ağrı hissedilmesi
• Kanlı kusma

Bu şikayetler genel itibari ile ortaya çıktığında daha farklı ve basit problemlerin belirtileri ile karıştırılabilir. Ancak mide kanseri açısından riskli bireylerde özellikle yutma ve yutkunma ile ilgili problemler varlığında ileri tetkik ve araştırmanın gerekli olduğu unutulmamalıdır.

Mide kanserinin ilerlediği vakalarda bu şikayetlerden farklı olarak daha ağır belirtiler de meydana gelebilir:

• Kansızlık
• Midede sıvı birikimi
• Gaita renginde koyulaşma
• Halsizlik
• İştah kaybı
• İstemsiz kilo verme

Stages of Stomach Cancer

After diagnosing stomach cancer, the doctor will stage the cancer. Staging determines the severity and treatment of cancer. Survival rates vary depending on the stage of cancer. In stage 0 stomach cancer, there are abnormal cells in the stomach. In stage 1, the muscle layer of the stomach and nearby lymph nodes are involved. In stage 4, the entire stomach is involved, and there is metastasis to distant organs and lymph nodes. The most severe stage is stage 4.

Diagnosis of Stomach Cancer

A patient who visits a doctor with the above-mentioned symptoms will first have their medical history taken. Symptoms, their duration, lifestyle, and habits are inquired about. Then, the following tests are conducted for diagnosis:

• Endoscopy: The most commonly performed procedure. During endoscopy, a biopsy is taken from the lesion and sent for pathological examination.
• Barium swallow x-ray: Previously used more frequently but now needed less often.
• Computed tomography (CT): Determines the location, size of cancer, and if there are nearby organ metastases.
• Laparoscopy: Performed under general anesthesia, a camera is used to view the stomach. The spread of cancer is assessed.
• Endoscopic ultrasound: The doctor evaluates the upper part of the stomach and esophagus with this method. Provides insight into the lesion.
• Chest X-ray: Provides insight into lung involvement.
• Magnetic resonance imaging (MRI): Used for cancer staging.
• Positron emission tomography (PET): Detects the location of active cancer cells.
• Kidney ultrasound: Provides insight into whether cancer has spread to the kidney.
• CEA (Carcinoembryonic antigen): Cancer antigens are checked in the blood.

Treatment of Stomach Cancer

The treatment of stomach cancer is conducted by a gastroenterologist, medical oncologist, cancer surgeon, and radiation oncologist. The stage of the disease is considered when planning treatment. The main treatment methods include:

• Surgery: Suitable for patients in stages 0, 1, 2, and 3. Depending on the stage of cancer, part or all of the stomach may be removed. Nearby lymph nodes are cleared. Even if cancer is in an advanced stage, surgery may be considered to prevent tumor bleeding and blockage of the stomach. This is called palliative surgery and is done to improve the patient's quality of life. If cancer is detected at a very early stage, it can be removed endoscopically. The surgery can be performed laparoscopically or as open surgery. During the operation, a tube may be placed into the intestine if it is anticipated that some patients will have difficulty feeding post-surgery, allowing liquid nutrients to be given directly to the patient's intestine. After stomach surgery, complications such as bleeding, clotting, and damage to nearby organs can occur. Sometimes, there can be leakage from the incision sites. Post-surgery, patients may experience nausea, heartburn, abdominal pain, and diarrhea. Patients should eat small, frequent meals. Vitamin supplements are given after surgery to prevent vitamin deficiencies.
• Chemotherapy: Can be started before or after surgery depending on the condition of the cancer. Chemotherapy before surgery is called neoadjuvant therapy, aimed at shrinking the tumor. After surgery, chemotherapy is repeated to kill any remaining cancer cells, known as adjuvant therapy. It can be combined with radiotherapy, especially for cancers that cannot be completely removed by surgery. Chemotherapy may be planned as the main treatment for metastatic stomach cancer. After chemotherapy, patients may experience nausea and vomiting, loss of appetite, hair loss, diarrhea, increased risk of infections, easy bruising due to low platelet count, fatigue, and shortness of breath. Cancer drugs can also cause neuropathy, heart damage, and hand-foot syndrome.
• New generation targeted drug therapy: These drugs help recovery by directly targeting cancer cells.
• Radiotherapy: Applied after surgery to kill any remaining cancer cells. Side effects of radiation therapy include skin redness, nausea, vomiting, diarrhea, fatigue, and decreased blood cell counts.
• Immunotherapy: This treatment helps the body's immune cells find and destroy cancer cells. Some patients benefit from this despite its side effects.

How to Prevent Stomach Cancer?

There is no certain way to prevent stomach cancer, but the risk can be reduced with some precautions. People with complaints such as stomach pain, indigestion, and bloating should not use stomach medication without consulting a doctor as it can delay diagnosis. The consumption of smoked and pickled foods, salted dried meat and fish can be reduced. Fresh vegetables and fruits should be increased. Whole wheat bread and legumes are beneficial. The fiber content in the diet should be increased. There are studies on the benefits of green tea. Weight control is necessary to reduce cancer risk as excessive weight increases cancer risk. Reducing salt and sugar is beneficial. Extremely hot beverages should be avoided. Regular exercise reduces the risk of all cancer types. Avoiding tobacco use is important. If Helicobacter pylori infection is detected, regular treatment should be carried out. Individuals with a genetic predisposition may undergo periodic screening, which can help in the early detection of this disease.