Gastric cancer represents an important cause of mortality worldwide. Frequency of gastric cancer differs significantly according to geographical areas and is directly related to eating habits, Japan as well as northern Europe have a high incidence of this type of cancer.
Gastric cancer is 2-3 times more common in men than in women and its frequency increases with age, average age of diagnosis is over 60 years. Occcurs rarely under the age of 45 years and gastric cancer rate started to decline in the last decade, with more frequent eradication of Helicobacter pylori infection.
Gastric Cancer Causes
Lately it was more well-established the relationship between infection with Helicobacter pylori and gastric cancer. World Health Organization (WHO) consider that Helicobacter pylori is the main factor in the development of gastric cancer, reason why it was called ” rank I oncogenic factor”. Fact that over a decade has passed to eradicate Helicobacter pylori infection, makes that gastric cancer incidence to be lower.
Gastric Cancer Risk Factors
Risk factors for gastric cancer are represented by:
- Eating habits. Increased content of nitrosamines in food preserved by salt and smoke are factors favoring the development of gastric cancer, in exchange, diet rich in fruits and vegetables with increased content of vitamin A and vitamin C, protects the stomach.
- Low socioeconomic status may be a contributing factor, probably through diet and infection with Helicobacter pylori.
- Genetic factor, proved by the existence of a family predisposition to this type of cancer.
- Helicobacter pylori infection is increasingly shown to contribute to development of gastric cancer. Helicobacter pylori has been classified by WHO as first order carcinogenic factor, is the first bacterium that is recognized to be involved in developing of a malignancy. Helicobater pylori intervention in gastric cancer development is achieved by inducing an atrophic gastritis with intestinal metaplasia, which has an evolutionary potential to dysplasia and finally to the development of gastric cancer.
Gastric disorders predisposing to gastric cancer are:
- Chronic atrophic gastritis, with intestinal metaplasia. Most often this type of gastritis is due to an infection with Helicobacter pylori.
- Gastric adenomatous polyps: is a premalignant condition, particularly those with large size, more than 1cm – 2cm diameter. Endoscopic polypectomy is indicated at the time of their discovery.
- Gastric resection in history, especially for gastric ulcer, is a risk factor for developing gastric cancer in longer than 15 years after resection. Usually there is an inflammatory gastritis of gastric stump, which can degenerate malignant. This makes the patient with stomach surgery, to be watched endoscopic more than 15 years after the surgery.
- Gastritis with giant folds, Menetriere gastritis, has a risk of 15% malignant. Fortunately, it is a very rare condition.
- Gastric ulcer, presents a low risk of malignancy, but often can be confused with an ulcerated gastric cancer, fact that requires biopsy of the lesion.
Gastric cancer symptoms can be polymorphic, depending on how advanced is the disease. Common symptoms are:
- Epigastric pain;
- Capricious appetite, which can go up to total loss of appetite or complete refusal to eating meat;
- Progressive weight loss, which in advanced forms can reach up to cachexia;
- Iron deficiency anemia;
- Less frequently digestive bleeding may occur, which will allow endoscopy diagnosis of gastric cancer;
- In advanced forms can be palpated an epigastric mass.
Quite often, gastric cancer can be discovered from an anemic syndrome with or without dyspeptic symptoms.
Early gastric cancer is usually asymptomatic or dyspeptic symptoms may appear subtle. Therefore, his discovery is often accidental, when performing an endoscopy for epigastric symptoms.
Gastric Cancer Morphopathology
Histologically, gastric cancer is a adenocarcinoma, which may appear as protruded, ulcerated or infiltrating cancer. Typical appearance of malignancy is the protruded form of cancer, that bleeds. Ulcerated gastric cancer may be confused endoscopically with gastric ulcer and therefore biopsy is needed to differentiate them.
Extension to nearby organs of gastric cancer (pancreas, transverse colon), appears early in general, as well as lymphatic extension of it. Metastasis is most commonly the liver and lungs and sometimes may occur carcinomatous peritonitis.
Staging of gastric cancer:
Staging of gastric cancer is made after TNM system (tumor, lymph node, metastasis) and allows the establishment of prognosis and therapeutic approach:
- T1: cancer affects mucosa and submucosa;
- T2: cancer affects muscular of the mucosa;
- T3: cancer affects gastric serosal;
- T4: cancer affects the surrounding organs.
- N0: no lymph node invasion;
- N1: the invasion of neighboring lymph nodes (up to 3 cm of tumor);
- N2: distant lymph nodes invasion.
- Mo: absence of metastases;
- M1: distant metastases.
Gastric Cancer Diagnosis
Most often the diagnosis start from dyspepsia, epigastric pain, weight loss or an unclear anemic syndrome. The presence of family aggregation of gastric cancer or precancerous lesions, can draw attention to the diagnosis of gastric cancer.
Physical exam is usually poor, but in advanced forms of gastric cancer is allowing the palpation of a epigastric mass or a subclavian adenopathy.
Laboratory analysis will usually show iron deficiency anemia. There are gastric cancers that may not be accompanied by anemia.
Gastroscopy is the elective diagnostic method. It allows viewing of the lesions, assessing their character and taking multiple biopsies to confirm the histological diagnosis of gastric cancer.
From Histologically point of view, gastric cancer is classified as follows: incipient gastric cancer (superficial, affecting the mucosa and submucosa) and advanced gastric cancer (affecting all layers of stomach). Endoscopic, advanced gastric cancer can be: protruded, infiltrating and ulcerated.
Incipient gastric cancer was classified in terms of endoscopic (Japanese classification of incipient gastric cancer) as follows:
- Type I: protruded type;
- Type IIa: superficial elevated type;
- Type IIb: superficial flat type;
- Type IIc: superficial depressed type;
- Type III: excavated type.
In incipient gastric cancer, survival at 5 years after surgery is about 95%.
Radiological examination with barium, a method that is outdated in terms of diagnosis, addressing in general to the advanced gastric cancer forms or gastric cancer infiltrating forms.
Abdominal ultrasound, allows highlighting the liver metastases or lymph node metastases.
Echo-endoscopy allows staging T (tumor) from TNM classification by assessing gastric parietal extension and the extension in regional lymph nodes.
Gastric Cancer Prognosis
The prognosis depends on theTNM extension of gastric cancer, histological type and age of the patient. Survival is good only in incipient gastric cancers, approximately 95% at 5 years. Surgery, with intent to eradicate gastric cancer is possible only in one third of cases, and in these survival at 5 years is about 25%.
Gastric Cancer Treatment
Elective treatment of gastric cancer is surgical. Gastric cancers surgically exceeded can be trated endoscopically. Incipient gastric cancer can be treated endoscopically too.
Preoperative and postoperative chemotherapy. Recent studies have suggested that preoperative application of chemotherapy followed by chemo-radiotherapy, cause a major histologic response which can lead to a increased survival rate.
Palliative chemotherapy is used in advanced gastric cancer.