Epidemiology and etiology
Historically, gastric cancer is considered the most common malignant tumor of the GI tract. At the same time, there is a clear trend toward a gradual decrease in incidence rates in developed countries.
The exact cause of the pathology has not yet been established. However, in clinical practice, immense importance is attached to precancerous conditions—background diseases in which the risk of malignant cell transformation increases manifold. These include:
- Chronic atrophic gastritis with reduced secretion (type A gastritis), associated with pernicious ($B_{12}$-deficiency) anemia.
- Polyps of the gastric mucosa.
- History of prior gastrectomy (gastric resection) for peptic ulcer disease.
Clinical presentation
A specific feature of the disease onset is that the first obvious signs are often already associated with the spread (metastasis) of the tumor. In middle-aged patients, the only initial signals may be mild dyspepsia—nausea and discomfort after meals.
Full-blown symptoms include the following manifestations:
- Changes in appetite: ranging from a significant decrease to complete absence. A specific symptom is the appearance of a selective aversion to food, primarily meat.
- Pain syndrome: occurs in approximately 25% of patients (a quarter of cases), while the clinical presentation may mimic an exacerbation of a common peptic ulcer.
- General symptoms: rapid weight loss (recorded in 50% of patients), progressive nausea and vomiting.
- Anemia: may develop early on due to constant micro-blood loss from the tumor tissue.
In rarer cases, the clinical presentation is complemented by paraneoplastic syndromes, such as prolonged unexplained low-grade fever, dermatomyositis, and neuromyopathy.
Physical examination and metastatic pathways
During objective examination of the patient in the early stages, routine propedeutics methods (palpation and percussion of the abdomen) are of low informational value. A tumor mass can only be detected physically in late stages, when the process has gone too far.
Features of metastasis:
- In the early stages, malignant cells affect regional lymph nodes of the abdominal cavity.
- In later stages, distant lymph nodes are involved. A classic example of lymphogenic spread is Virchow's metastasis (involvement of the left supraclavicular lymph node).
- Through hematogenous and implantational pathways of metastasis, secondary foci form in the liver, ovaries, and other internal organs.
Diagnostic methods and treatment tactics
A complex of instrumental and laboratory studies is used to confirm the diagnosis.
Instrumental diagnostics:
- «Gold standard»: fiberoptic esophagogastroduodenoscopy (EGD) with targeted biopsy of altered areas. Following the procedure, a morphological (histological) examination of the obtained biopsy specimen is mandatory.
- Gastric X-ray: performed with double contrast. The main radiological sign of malignant growth is the "filling defect" sign with uneven, eroded contours.
Laboratory data:
- Complete blood count: pathological changes are detected in 2/3 of patients. An increase in ESR and the development of anemia are noted. Anemia can be iron deficiency (due to chronic micro-hemorrhages) or pernicious ($B_{12}$-deficiency).
- Gastric secretion study: a sharp decrease in gastric juice acidity is characteristic, up to the development of complete achlorhydria (absence of hydrochloric acid).
Treatment tactics for a confirmed diagnosis are unequivocal: surgical intervention—gastric resection—is the only effective method of helping the patient.
Briefly: answers to topical questions
What specific distant metastases of gastric cancer exist besides Virchow's node?
In addition to Virchow's node, specific distant metastases of gastric cancer include lesions of the ovaries, pelvic cellular tissue, axillary lymph nodes, and the umbilicus.
The following eponymic and specific localizations are distinguished:
- Krukenberg tumor — distant retrograde or implantational metastasis to the ovaries.
- Schnitzler's metastasis — dissemination to the lymph nodes of the pararectal tissue (tissues of the pelvic floor).
- Irish's node — lymphogenic spread to the axillary lymph nodes.
- Umbilical metastasis — a lesion occurring via the spread of tumor cells along the round ligament of the liver.
Three typical precancerous conditions can be remembered by the acronym GAP: Atrophic gastritis, History of resection (for ulcer), Polyps.
Class and exam questions
Which method is considered the gold standard for diagnosing gastric cancer?
The gold standard is performing EGD with a targeted biopsy of the suspicious area and mandatory subsequent morphological examination of the biopsy.
Where is Virchow's metastasis localized?
This is a specific lesion of the left supraclavicular lymph node that occurs via the lymphogenic pathway of tumor metastasis.
Which radiological sign is characteristic of this tumor?
Double-contrast X-ray reveals a "filling defect" with uneven and eroded contours.
Why does anemia frequently develop in gastric cancer?
Anemia can be iron deficiency due to chronic occult micro-hemorrhages from a disintegrating tumor, or pernicious against the background of precancerous type A atrophic gastritis.
What else to study on this topic
- Mechanisms of development of paraneoplastic syndromes (dermatomyositis, neuromyopathy)
- Radiological picture: the "filling defect" sign
- Types of surgical treatment and scopes of gastric resection
- Differential diagnosis of pain in peptic ulcer disease and gastric cancer
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