Pathology

There are several pathologic variants of gastric adenocarcinoma. In the intestinal form, the malignant cells form gland-like structures. This type is more frequently

associated with gastric mucosal atrophy, chronic gastritis, intestinal metaplasia, and dysplasia. This is the most common pathological variant.

The diffuse variant of gastric adenocarcinoma lacks gland formation. It is characterized, rather, by sheets of loosely adherent cells. This type tends to occur in younger patients and accounts for a higher proportion of cases that occur in low-risk areas. It is less common and associated with a poorer prognosis than the intestinal type.

Gastric carcinomas occur with equal frequency in the proximal and distal stomach. About 40% occur in the proximal stomach, 40% in the distal stomach, and about 20% have diffuse involvement. Distal tumors tend to have a better prognosis. Approximately 15% of gastric cancers will have nodal metastasis at the time of diagnosis.

TNM Classification

The TNM classification system stages tumors based on the depth of tumor invasion, nodal involvement, and the presence or absence of distant metastasis. A summary of this classification is as follows (Tables 11.2, 11.3 and 11.4):

Management

Surgical resection affords the only hope for cure. However, an advanced stage of disease at the time of diagnosis precludes this possibility in many patients. Carcinomas of the distal stomach are often treated with subtotal gastrectomy. More proximal lesions may require total gastrectomy or even esophagogastrectomy for adequate resection. These tumors often demonstrate extensive intramural spread. For this reason, wide margins of resection around the tumor are required. Retrospective studies have suggested that margins of 6 cm around the gross tumor are required to minimize the rate of local recurrence. As would be expected, microscopic disease at the

Table 11.2. Staging for gastric cancer

Tumor

T1 tumor confined to mucosa

T2 involves mucosa and submucosa, extends to but does not penetrate serosa

T3 penetrates serosa with or without invasion of adjacent structures T4 diffuse involvement on gastric wall (linitis plastica)

Nodes

NO no nodal metastasis

N1 metastasis to perigastric lymph nodes in immediate vicinity of tumor

N2 metastasis to lymph nodes distant from primary tumor or along both curvatures of the stomach

Metastasis

Table 11.3. Stage groupings for gastric carcinoma

Stage Grouping

Stage IV Tumor unresectable or metastatic

Table 11.4. Survival rates for gastric carcinoma

Stage Survival

Stage I approaching 100% 5-year survival

Stage II 50°% 5-year survival, approx. 70% 1-year survival

Stage III 10°% 5-year survival, approx. 60% 1-year survival

Stage IV < 5% 5-year survival, approx. 20% 1-year survival

Table 11.5. Complications of anti-ulcer surgery

Parietal Cell Vagotomy

Vagotomy and Pyloroplasty

Vagotomy and Antrectomy

Mortality Ulcer recurrence Dumping Diarrhea

margin of resection is associated with a high rate of local recurrence and a poorer prognosis. Extended lymphadenectomy is commonly practiced in Japan. The value of this, however, is debated.

Palliative surgery is commonly entertained in cases of advanced disease. Surgical palliation often takes the form of gastric resection. While resection does not extend survival over that seen with bypass of obstructing lesions, it does provide improved symptomatic relief. Mean survival after palliative resection is approximately 9 months. Endoscopic laser fulguration is also sometimes an option for palliation.

Chemotherapy for gastric adenocarcinoma is of limited utility. Single-agent treatment regimens with 5-FU, mitomycin C, or doxorubicin have led to partial responses in about 25% of cases. Better response rates have been seen with multi-agent regimens, but survival rates have not been significantly influenced. Adjuvant chemotherapy after potentially curative surgery has no proven benefit. Radiotherapy has shown only modest benefits.

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment