Gastric Cancer Quiz: Oncology Review

Adenocarcinoma accounts for approximately 90 to 95 percent of all gastric carcinomas. It arises from the glandular epithelium lining the stomach. Other malignancies such as lymphoma, squamous carcinoma, and stromal tumors occur far less frequently. Epidemiological data consistently show adenocarcinoma dominance worldwide, particularly in regions with high Helicobacter pylori prevalence, making it the most clinically significant and commonly tested gastric malignancy type.

The pre-pyloric region, located near the distal stomach, is most frequently involved in gastric adenocarcinoma. Chronic inflammation from Helicobacter pylori often predominates in the antral region, promoting intestinal metaplasia and dysplasia. Statistically, distal tumors historically represented the majority of cases, although proximal cancers are increasing. Anatomical exposure to bile reflux and dietary carcinogens contributes to higher malignancy rates in this area.

Helicobacter pylori infection induces chronic gastritis, leading to atrophy, intestinal metaplasia, dysplasia, and eventual carcinoma. The bacterium increases inflammatory cytokines and promotes genetic instability. Studies estimate infected individuals have a two to six times higher risk of gastric carcinoma. This strong epidemiological and mechanistic association makes Helicobacter pylori the most established and preventable risk factor globally.

Nitrosamines, formed from nitrates and nitrites in smoked and salted foods, are potent carcinogens. They cause DNA alkylation and mutation in gastric epithelial cells. High dietary salt enhances mucosal damage and facilitates carcinogen penetration. Populations consuming preserved foods show significantly increased gastric cancer incidence, supporting dietary nitrosamine exposure as a major environmental contributor to malignancy development.

Gastric adenoma is a dysplastic epithelial lesion with malignant transformation potential. It represents a step in the adenoma to carcinoma sequence. Chronic autoimmune gastritis and intestinal metaplasia also increase risk. Surveillance studies demonstrate that high-grade dysplasia within adenomas progresses to carcinoma in a measurable percentage of patients, warranting close monitoring and excision.

Diffuse scirrhous carcinoma infiltrates the stomach wall extensively, producing fibrosis and thickening. This results in a rigid, non-distensible stomach termed leather-bottle stomach or linitis plastica. The fibrotic reaction reduces gastric compliance and volume. This macroscopic pattern is characteristic of diffuse-type carcinoma and correlates with aggressive biological behavior and poorer prognosis compared to localized polypoid lesions.

Intestinal-type gastric carcinoma forms gland-like tubular structures resembling intestinal epithelium. This differentiation reflects stepwise progression from metaplasia to dysplasia to carcinoma. Histologically identifiable gland formation distinguishes it from diffuse type, which lacks cohesion. Epidemiological data show intestinal type is more common in high-risk regions and often associated with environmental and dietary risk factors.

Signet ring cells contain abundant intracellular mucin that displaces the nucleus to the cell periphery. This creates a ring-like appearance under microscopy. The mucin accumulation disrupts cell adhesion and promotes diffuse infiltration. These cells are characteristic of diffuse-type adenocarcinoma and are associated with aggressive tumor spread and poorer survival outcomes compared to gland-forming tumors.

Lymphatic spread is the most common route because the stomach has an extensive lymphatic network. Tumor cells enter regional lymphatics and metastasize to perigastric and celiac nodes. Clinical staging data show nodal involvement occurs early in disease progression. The high density of lymphatic drainage pathways explains why nodal metastasis is frequently detected even in relatively small primary tumors.

Krukenberg tumors are bilateral ovarian metastases, typically from signet ring cell gastric carcinoma. Tumor cells spread transcoelomically across the peritoneal cavity and implant in ovarian tissue. Histology shows mucin-filled malignant cells within ovarian stroma. Their bilateral nature and metastatic origin distinguish them from primary ovarian cancers, carrying significant diagnostic and prognostic implications.

Early gastric cancer is defined as carcinoma confined to the mucosa or submucosa, regardless of lymph node status. Depth of invasion determines classification rather than metastasis presence. Studies demonstrate that when confined to these layers, surgical resection yields excellent survival outcomes. Muscularis propria involvement automatically classifies the tumor as advanced disease.

Early gastric cancer has an approximately 95 percent five-year survival rate after curative resection. Limited depth of invasion reduces systemic spread and enables complete surgical removal. Screening programs in countries like Japan show markedly improved survival due to early detection. This survival percentage significantly exceeds that of advanced gastric carcinoma, which often falls below 30 percent.

Endoscopic biopsy provides histological confirmation, which is the diagnostic gold standard. Imaging cannot reliably distinguish benign from malignant ulcers. Tissue examination reveals cellular atypia, invasion, and architectural distortion. Multiple biopsies are often taken to improve sensitivity. Accurate diagnosis is critical because management differs significantly between benign peptic ulcer disease and malignant gastric carcinoma.

The liver is the most common organ involved in hematogenous spread due to portal venous drainage from the stomach. Tumor cells enter the portal circulation and seed hepatic tissue. Clinical data show liver metastases are frequently detected in advanced gastric carcinoma. This vascular pathway explains the high prevalence of hepatic involvement compared to other distant organs.

Transcoelomic spread occurs when malignant cells exfoliate from the primary tumor into the peritoneal cavity. These cells implant on peritoneal surfaces and ovaries. Peritoneal fluid circulation facilitates distribution. Krukenberg tumors arise through this mechanism. This route differs from direct invasion or lymphatic spread and indicates advanced intraperitoneal dissemination with significant prognostic impact.