- Who Gets Stomach Cancer and How Often?
Stomach cancer is still among the most common cancers all over the world. There is a significant difference in the incidence of stomach
cancers geographically from region to region.
Despite its decreasing frequency in Western countries, it is still an important
health problem in our country and Asian countries. An interesting observation is that a remarkable decrease in the incidence of stomach cancer has been detected in people who migrate from countries with a high
incidence of stomach cancer to countries with a low
incidence of this cancer. Among those who immigrated from Japan to America, a decrease is clearly evident in those born and raised in the new country. Environmental factors of the host country
play a role in this. It is also important that the migrating population changes their dietary habits over time and adapts to the food culture of their new society.
Stomach cancer occurs twice as often in men than in women. Starting from the fourth decade, there is an increase in its incidence with increasing age, reaching its highest levels between the ages of 60-70. Although the frequency of stomach cancer is decreasing, it has an important place among cancer deaths because it is usually diagnosed in advanced stages. Early diagnosis and treatment ensure a good prognosis in cancer treatment. Therefore, identifying and following patients at risk for stomach cancer
will increase the success of treatment.
- What are the Causes of Stomach Cancer?
Various risk factors are blamed for stomach cancer. These risk factors include environmental, genetic and familial factors. Smoking, family history, male gender,
white race, A blood type, old age, low socioeconomic status and previous stomach surgeries
increase the risk of stomach cancer. In patients where a part of the stomach has been removed for reasons other than cancer, cancer may occur in the remaining stomach tissue within 15-
20 years. It is thought that a decrease in stomach acid or bile reflux may cause this. Clinical conditions such as achlorhydria, atrophic gastritis, in which stomach acid production is reduced, or polyps and intestines formed in the stomach wall Changes such as nal
metaplasia can lead to stomach cancer. Other environmental and personal causes
include exposure to lead, nickel, coal, rubber and asbestos.
Helicobacter pylori infection is also an important causal factor. Since Helicobacter pylori
infection is frequently seen in patients with gastritis and ulcers, it is thought that it may pave the way for gastric mucosal damage and
atrophic gastritis that develops as a result.
Compounds such as nitrosamines released locally due to bacterial infection enter the stomach
It is thought that it may contribute to the formation of cancer.
The main risk factors thought to cause stomach cancer are those related to diet.
There is a close relationship between dietary habits and stomach cancer. Nitrates and nitrites used to preserve foods for long periods of time are thought to increase the risk of stomach cancer. It has been shown that the risk increases with a diet low in milk,
fresh vegetables and fruits, and lacking vitamins A and vitamin C, and with eating fried foods,
smoked, dried, salted foods, especially fish
that have undergone these processes. It has also been shown that smoked fish extracts are mutagenic and that this mutagenesis can be prevented with vitamin C. The protective effects of fresh fruits and vegetables
have been demonstrated. Likewise, it is stated that the use of refrigerators and the development of freezing
storage methods have caused a decrease in the frequency of stomach cancer.
- How Does Stomach Cancer Occur?
The stomach is an organ located in the upper abdomen, just below the ribs in the digestive system. The stomach wall is extremely thick and consists of five layers. Stomach cancers
originate from the membrane surrounding the stomach called mucosa. As the cancer grows, it passes through this lining
first into the underlying support tissue and then into the thick muscle layer. Finally, it passes through the outermost layer called serosa and spreads to neighboring organs. For this reason, intra-abdominal membrane (peritoneal) spread is common.
When diagnosed in a significant proportion of patients, there is local or distant
spread by these means. Most stomach cancers are in the form of ulcers and may look like benign stomach ulcers. However, features such as the ulcer being larger than 2 cm and its edges being raised from the surface suggest the possibility of cancer.
- How Does Stomach Cancer Cause Symptoms?
The stomach is the organ with the thickest wall and the widest internal cavity
among the organs that make up the digestive system. Due to these features, stomach tumors can reach large diameters and may not cause symptoms for a long time before being diagnosed. The fact that stomach cancers do not cause symptoms in the early stages or have very vague symptoms makes early diagnosis difficult. Therefore
all complaints of patients should be investigated. Because early diagnosis is very
important in stomach cancer. In diagnosed cases, the chance of cure with surgery is very high.
The most common complaints of patients with stomach cancer are discomfort in the upper abdomen that they cannot fully explain, pain in the same area, loss of appetite, weight loss and fatigue. Symptoms such as difficulty in swallowing,
nausea, vomiting, anemia and weakness and fatigue due to anemia are also frequently
encountered. In more advanced stages, bloating, difficulty swallowing, abdominal pain or early feeling of fullness
occur. Some of the patients present with stomach bleeding, fluid accumulation in the abdomen, jaundice, or a palpable mass. Symptoms may vary depending on the location of the cancer in the stomach. For example,
difficulty in swallowing is prominent in a tumor located at the junction with the pharynx, while
findings related to obstruction and enlargement of the stomach are evident in a tumor located at the exit of the stomach.
- <. strong>How is Stomach Cancer Diagnosed?
As with all other cancers, early diagnosis is important in stomach cancer. For this
all non-temporary complaints of patients, even if mild, should be considered worthy of investigation.
Endoscopy is the gold standard for the diagnosis of stomach cancer. In this method, popularly known as "throwing a tube into the stomach"
, the inner surface of the stomach is visualized with a flexible tube of approximately 1 cm in diameter. If a finding is detected, a biopsy can be performed with the help of a wire with a clip on its end. Abdominal ultrasonography is useful both in the diagnosis of the primary disease and in the detection of spread such as liver metastases. It may be useful. Endoscopic ultrasonography has now begun to be used more and more frequently. It is an effective non-invasive method, especially in the diagnosis of early stomach cancer, as it shows which layers of the stomach the primary tumor has spread (T stage). It is the best method to show lymph node involvement. Apart from this
, computed tomography and PET-CT are frequently used for staging purposes.
- How is Stomach Cancer Treated?
Surgery, radiotherapy and chemotherapy are used alone or combined
in the treatment of stomach cancer. In early stomach cancers (tumor limited to the mucosa and submucosa), there is a chance of cure with surgery alone. Survival rates increase with protective
(adjuvant)radiotherapy and chemotherapy in stomach cancer after curative surgery. In the metastatic stage
chemotherapy is applied for palliative purposes. In general, stomach cancers are now among the cancers that are sensitive to
chemotherapy.
1. Surgery
Surgery is considered the main treatment for stomach cancer. With Billroth's successful partial gastrectomy for stomach
cancer in 1881, it was put forward that the treatment of these patients might be possible. Today, instead of performing total gastrectomy; Depending on the
location and size of the tumor, it is accepted that removing the affected cancerous part of the stomach (partial
or subtotal gastrectomy) is sufficient.
2. Radiotherapy
Radiotherapy can be given as a preventive (adjuvant) after surgery for stomach cancer.
The aim here is to reduce the risk of local-regional recurrence. Especially if there is lymph node involvement, the risk of recurrence is high. For this reason, these patients are given preventive chemotherapy and
radiotherapy after surgery. Radiotherapy is also used as primary treatment in patients who do not have a chance for surgery. Symptomatic recovery and long survival may be possible with doses of 4500-6000 cGy.
3. Chemotherapy
Preventive (Adjuvant) Chemotherapy in Early Stage Stomach Cancer:
The justification for preventive chemotherapy is the local or microscopic residual after surgery. is to eliminate metastatic
disease and reduce the possibility of recurrence. Preventive chemotherapy must be given, especially in locally advanced but operable tumors (T3-T4, N1-N2, M0)
that are thought to be completely removed surgically. Recently, in these patients, it has become more important to shrink the tumor with
chemotherapy before surgery and submit it to surgery. Especially
for locally advanced tumors and suspicion of lymph node metastasis, preoperative chemotherapy is now recommended in international treatment guidelines and is being applied more and more frequently in our country. However, it should not be forgotten that there is a 15-20% risk of tumor growth in these patients while receiving chemotherapy.
Chemotherapy in Advanced Stomach Cancers:
Combined chemotherapy. Combinations containing platinum and 5-FU were most commonly used. The most commonly used combination is cisplatin and 5-FU/capecitabine. The XELOX scheme, which is obtained by replacing cisplatin with oxaliplatin
, is well tolerated by patients with its lower side effect profile and has become increasingly popular in recent years. As a result, disease control rates of up to 70-80% have been reported with existing chemotherapy schemes in advanced
stomach cancers.
- Targeted Smart Therapies in Stomach Cancer
Better understanding the molecular basis of cancer has led to the development of targeted therapies that affect cell differentiation, proliferation and survival. A protein antibody called trastuzumab has been developed against the HER2 (c-Erb-B2) oncogene, which belongs to the epidermal growth factor receptor (EGFR) family. Proving that trastuzumab, when added to chemotherapy, prolongs survival in HER2-positive
metastatic gastric cancer, is the most important development in this field in recent years.
Randomized phase 3 TOGA study in HER2-positive metastatic gastric cancer
HER2 positivity was detected in 22.1% of patients. A significant survival advantage was detected with the addition of trastuzumab to the treatment, especially in patients with immunohistochemistry 3+ or
2+/FISH+. The response rate to treatment was higher in patients receiving trastuzumab than in the chemotherapy arm.
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