Stomach Cancer occurs in the upper part of the abdomen, between the esophagus and the duodenum. Like other digestive system tumors, stomach cancers develop from the mucous membrane layer. The most common type of cancer is called adenocarcinoma. Tumors of the adenocarcinoma type have subtypes such as mucinous and signet ring cell tumors. These subtypes are often associated with a poor prognosis. Stomach tumors are named according to the regions of development. Tumors in the region where the stomach connects to the esophagus are called cardia tumors, while tumors in the body of the stomach are referred to as corpus tumors, and those at the exit of the stomach are known as antrum tumors.
What are the Symptoms of Stomach Cancer?
Stomach cancers, which often do not show symptoms in the early stages, are usually diagnosed when a symptom manifests. In other words, many stomach cancer patients experience symptoms, and only a limited number are incidentally detected during screening endoscopy.
The most common symptoms in stomach cancers are persistent abdominal pain and weight loss. Weight loss occurs due to reduced food intake related to reasons such as early satiety, difficulty swallowing, and a sensation of blockage after swallowing. Additionally, abdominal pain after food intake, nausea, and vomiting discourage patients from eating, leading to continued weight loss.
Since there is occult bleeding in the form of blood loss from stomach tumors, anemia symptoms such as weakness, palpitations, a tendency to sleep, and easy fatigue can be observed. Iron deficiency or vitamin B12 deficiency may also occur in these patients. Severe bleeding, such as vomiting blood or blood in the stool, can be expected in less than 20% of patients with stomach cancer.
In a patient presenting with abdominal pain, the presence of a palpable mass in the upper middle abdomen may indicate an advanced stage of stomach tumor. Swelling above the left clavicle, a hard lump around the navel, or a lump under the left armpit detected during a general examination by a doctor may be associated with the spread of stomach cancer to lymph nodes.
In patients with stomach cancer spreading to the liver, symptoms may include jaundice, persistent pain in the upper right abdomen, and pain in the back. Accumulation of fluid in the abdomen and abdominal distension can be detected due to its spread to the peritoneum.
Approximately one-fourth of patients diagnosed with stomach cancer may report a history of past stomach ulcers and related issues.
To summarize and emphasize again, the alarming symptoms that raise a high suspicion for stomach cancer include:
- Early satiety, bloating
- Vomiting after a while of eating
- Involuntary weight loss
- Stomach bleeding
- Difficulty swallowing, difficulty in the passage of food to the stomach, a sensation of blockage
- Severe, persistent pain in the stomach
Risk Factors for Stomach Cancer
Numerous environmental and genetic factors have been identified for stomach cancer, with approximately 90% of all stomach cancers known to develop due to environmental causes. The listed risk factors below have a certain impact on the development of stomach cancer. Reviewing modifiable, preventable, or avoidable risk factors, as with any disease, can reduce the risk of stomach cancer. For detailed information on hereditary syndromes related to stomach cancer, you can refer to the section “Is Stomach Cancer Hereditary?”
- Family history of stomach cancer,
- Untreated stomach ulcers,
- Presence of Helicobacter pylori bacterium in the stomach,
- History of stomach surgery,
- Atrophic gastritis,
- High salt consumption,
- Consumption of pickled foods,
- Smoking,
- Consumption of processed meats (sausages, salami, sucuk, etc.),
- Obesity,
- Epstein-Barr virus infection,
- FAP syndrome,
- Lynch Syndrome and other hereditary cancer syndromes,
- Blood type A.
Endoscopic screening of high-risk patients is important for early diagnosis. On the other hand, patients showing symptoms of the digestive system should also be evaluated through gastroscopy.
Stomach Cancer Staging
Upon the detection of stomach cancer during endoscopy, certain tests should be conducted to determine the stage of the disease and, consequently, to plan its treatment.
In staging:
- Upper abdomen (abdomen) computed tomography,
- Lower abdomen (abdomen) computed tomography,
- Thoracic (lung) computed tomography,
- Upper abdomen magnetic resonance imaging (should be taken in cases suspected of liver metastasis),
- PET-CT
- These are recommended for tumors that are not limited to the inner layer of the stomach and for tumors without clear signs of spread on the tomography (not contributing to treatment planning in cases with metastasis),
- Endoscopic ultrasound (can evaluate the extent of spread in the wall in early-stage tumors),
- Staging laparoscopy
- This approach is used in staging the disease, especially in cases where chemotherapy is initially recommended. Before treatment, the procedure involves examining the inside of the abdomen through laparoscopic (closed) methods after the patient is taken into surgery. The aim is to identify the spread on the peritoneum, which is detected in about 20-30% of stomach cancers where spread is not observed on tomography, in order to plan the treatment.
Current data in our country indicates that stomach cancers are detected in approximately 27% of patients with limited disease only in the stomach, about 43% with disease in the stomach and surrounding lymph nodes, and in about 30% of patients with metastasis (spread) to organs outside the stomach.
Stomach Cancer Treatment
Patients properly staged should be evaluated in multidisciplinary cancer councils, and a suitable treatment plan should be devised based on the stage. Different approaches exist in the application of treatment based on stages in Far East countries, where there is substantial expertise in stomach cancer treatment, compared to America and European countries. Accordingly:
European / American Approach:
- For very superficial tumors (T1a), nonsurgical treatment can be provided with endoscopic submucosal dissection.
- Neoadjuvant (preoperative) chemotherapy is administered for tumors invading the muscle layer of the stomach (T2 and above) or spreading to nearby lymph nodes (lymph node positive).
- Chemotherapy is given in cases of metastatic (spread to distant organs) disease.
- Direct surgery can be applied in selected cases.
Far East Approach:
- Nonsurgical treatment with endoscopic submucosal dissection is possible for very superficial tumors (T1a).
- Surgery is performed for T1, lymph node-negative patients.
- For T1, lymph node-positive patients, surgery is carried out using the D2 dissection technique.
- For T2,3,4 patients with intense lymph node involvement, neoadjuvant chemotherapy is recommended. If there is no intense lymph node involvement, surgery is primarily performed using the D2 dissection technique.
- Chemotherapy is given in cases of metastatic (spread to distant organs) disease.
Although there are differences between countries and schools of thought, neoadjuvant chemotherapy is considered appropriate for more patients nowadays. For more information on this topic, you can refer to the section “Administering Chemotherapy Before Surgery in Stomach Cancer.”
The D2 dissection technique involves not only removing the tumor-affected part of the stomach in classical surgery but also extracting deep lymph nodes around the celiac artery and its branches. Studies in the Far East and subsequently in Europe have demonstrated high survival rates and tumor eradication in patients with positive lymph nodes using the D2 dissection technique, compared to classical surgery. It is crucial for the D2 dissection technique, which is slightly more challenging than classical surgery, to be performed by experienced surgeons. Today, it is possible to perform the classical or D2 dissection technique using open, laparoscopic, or robotic methods. The appropriate technique can be applied considering the patient’s characteristics, the surgeon’s experience, and the infrastructure of the center. For detailed information about stomach cancer surgery, you can access the section “How Is Stomach Cancer Surgery Performed?”
Disease Progression in Stomach Cancer
Despite the application of appropriate treatments, similar to all cancers, disease recurrence is possible in patients diagnosed with stomach cancer, leading to cancer-related deaths. Proportionally, the 5-year survival rate is observed to be 70% in patients who have received treatment for cancer limited to the stomach, while it is 32% for those with disease in both the stomach and lymph nodes. Patients diagnosed with metastasis to distant organs at the time of diagnosis can only achieve a 5-year survival rate of about 6%.
In contemporary times, advancements in technology, refined surgical techniques, increased experience of surgeons in cancer surgery, and enhanced effectiveness of oncological treatments contribute to improved survival and cancer remission rates.
