Stomach cancer, also known as gastric cancer, occurs as a result of abnormal cell growth. It develops slowly over many years. Before the appearance of cancer, precancerous changes can be seen in the mucosa, which is the inner lining of the stomach. Such changes rarely cause symptoms and therefore often go unnoticed, making the diagnosis even more challenging.
Gastric cancer can affect any part of the stomach, although it is most commonly seen in a region called the body of the stomach. The adenocarcinoma type is responsible for about 95% of stomach tumor cases.
Stomach adenocarcinoma mostly affects men around 60-70 years of age. About 80% of patients are over 50 years old. In Brazil, stomach cancer is the third most frequent type among males and the fifth among females. It is estimated that in 2020 there will be 21,230 new cases, 13,360 in men and 7,870 in women.
Other types of tumors (besides adenocarcinomas) can also occur in the stomach. Lymphomas are diagnosed in about 3% of cases and sarcomas, considered rare tumors, start in the tissues that give rise to muscles, bones and cartilage as gastrointestinal stromal tumors, better known as GISTs.
Types of stomach cancer
Adenocarcinomas can be divided into two types, according to the pathology: intestinal and diffuse type.
Learn more about them below:
- Intestinal type – the intestinal type commonly occurs in older patients, mostly male, and is associated with the presence of chronic atrophic gastritis and intestinal metaplasia (set of small lesions) resulting from chronic gastric inflammation related to H. pylori infection;
- Diffuse type – the diffuse type occurs in younger patients, with equal distribution between the sexes and exhibits a more aggressive behavior when compared to the intestinal type. It originates from normal gastric epithelium, with no apparent pre-cancerous lesion, and may be related to a genetic mutation (of a gene called CDH1).
Symptoms and signs of stomach cancer
There are no specific symptoms that lead to a quick identification of stomach cancer. However, some signs may indicate the development of a stomach tumor:
- Weight loss;
- Loss of appetite;
- Bloating (feeling of a full stomach);
- Difficulty swallowing;
- Persistent abdominal discomfort.
These symptoms, however, are common to several other benign diseases, such as ulcers and gastritis. Therefore, noticing them is not synonymous with having stomach cancer. For this reason, it is necessary to consult with a specialist doctor experienced in detecting the symptoms and signs of the disease.
During the physical examination, the cancer patient may feel pain when the stomach is palpated. If there is an increase in the size of the liver and the presence of swollen lymph nodes in the lower left area of the neck and nodules around the belly button, the doctor may consider them to be signs that the disease is at a more advanced stage.
Vomiting blood occurs in about 10 to 15% of stomach cancer cases. In addition, changes such as blood in the stool, dark, pasty stools with a very strong odor (indicative of digested blood) can be observed.
Stomach cancer diagnosis
The diagnosis of gastric cancer is made by upper digestive endoscopy. To perform this exam, the patient is sedated and receives local anesthesia in the throat region, so that a tube is introduced through the mouth.
Upper endoscopy allows the doctor to view the esophagus and stomach, in addition to doing biopsies (taking small samples of tissue). The biopsy material is sent to a laboratory to confirm (or not) the diagnosis of malignant tumor and define its type.
If the diagnosis of gastric cancer is confirmed, additional tests may be necessary, such as computed tomography, which assesses the extent of the tumor.
On the other hand, when the cancer appears to be at an earlier stage, endoscopic ultrasound (exam similar to upper digestive endoscopy, in which an ultrasound device is placed at the end of the tube introduced through the throat) may be sufficient.
Depending on the case, the doctor may opt for exploratory surgery to look for signs that the cancer has spread beyond the stomach (metastasized). It is usually done laparoscopically, which means the surgeon makes small incisions in the abdomen and inserts a special camera that transmits the images to a monitor in the operating room.
Treatment options for stomach cancer depend on its location, its stage and how aggressive the disease is. In addition, the physician needs to take into account the patient’s general health status and preferences. Understand, below, how the main alternatives available to doctors apply.
Surgery – The main goal of surgery is to remove all of the cancer and also a portion of the healthy tissue around it, a procedure called a surgical margin. The types of surgery for gastric cancer are:
- Removal of early-stage tumors from the stomach lining;
- Removal of part of the stomach (subtotal gastrectomy)
- Complete removal of the stomach (total gastrectomy)
- Removal of lymph nodes for testing for the presence of cancer;
- Surgery to relieve signs and symptoms.
Chemotherapy – It can be started before surgery (known as neoadjuvant therapy) as a way to help shrink the cancer, thus making it easier to remove. It can also be prescribed after surgery (adjuvant chemotherapy) to eliminate cancer cells that remain in the body.
Radiotherapy – Like chemotherapy, it can be done before surgery to reduce the size of the tumor, or later to eliminate any remaining cancer cells. In advanced cancer that cannot be operated on, radiation therapy can be used to relieve adverse effects, such as bleeding, that can occur as the tumor grows. Depending on the case, the doctor may combine chemotherapy with radiotherapy.
Targeted Therapies – Targeted therapies specifically focus on the weaknesses of cancer cells, leading to their death. In gastric cancer, the use of targeted therapies is usually associated with chemotherapy.
Immunotherapy – Immunotherapy is a treatment that helps the immune system fight cancer. Normally, the immune system cannot attack the cancer, because cancer cells produce proteins that make it difficult for immune system cells to recognize them as dangerous. Immunotherapy works by interfering with this process.
There are several factors that can increase your risk of stomach cancer:
- Gastroesophageal reflux disease;
- Diet rich in sodium (salt) and smoked foods;
- Low consumption of fruits and vegetables;
- Family history;
- Pylori virus infection;
- Stomach polyps;
To avoid the risk of developing stomach cancer, it is important to avoid the factors described above. Maintaining a healthy weight according to your age, height and body structure, opting for a diet with more natural ingredients, with a focus on vegetables and fruits, reducing the amount of salt and processed foods in your diet and not smoking are behaviors that reduce the risk of getting the disease.