Residual gastric cancer (cancer of gastric remnant), also known as postgastrectomy gastric cancer, can occur in the residual stomach after partial gastrectomy, as well as in the entire stomach following simple gastroenterostomy, simple perforation repair, or vagotomy. It is generally defined as gastric cancer that develops after surgery for non-cancerous diseases of the stomach. If the initial surgery was performed for malignant disease, the term applies only to gastric cancer occurring more than 20 years postoperatively. Residual gastric cancer accounts for 0.4% to 5.5% of all gastric cancers, with reported incidence rates varying between 1% and 5%. The male-to-female ratio is 5.4:1, and the average age of onset is 65 years. The interval between gastric surgery and the development of residual gastric cancer varies in the literature, averaging 13 to 19 years, with the longest reported interval being 40 years. A few cases occur within less than 10 years. Generally, the incidence of residual gastric cancer is lower than that of gastric cancer in the general population within the first 15 years after surgery. However, beyond 15 years, the incidence gradually increases, and after 20 years, it becomes 6 to 7 times higher than in the general population. Consequently, the previous belief that early gastrectomy could prevent the malignant transformation of peptic ulcers has been disproven. The incidence of residual gastric cancer is similar after both gastric and duodenal resection. The likelihood of its development is related to the initial surgical approach. Patients who undergo Billroth II reconstruction or simple gastrojejunostomy after subtotal gastrectomy are more prone to residual gastric cancer than those who undergo Billroth I reconstruction. The most common site of residual gastric cancer is the anastomotic region, though it can also diffusely involve the entire residual stomach.

After subtotal gastrectomy or vagotomy, the stomach enters a state of low or no acid secretion, coupled with a decrease in gastrin secretion, which reduces protective mucus, leading to gradual atrophy of the gastric mucosa. Additionally, the reflux of bile, pancreatic juice, and intestinal fluid after gastric surgery further damages the gastric mucosa, resulting in chronic atrophic gastritis, intestinal metaplasia, and atypical hyperplasia, which are important factors in the development of remnant stomach cancer.

The reduction in gastric acid after surgery promotes bacterial growth and proliferation in the stomach. Bacterial toxins and metabolites from the breakdown of bile by bacteria may have carcinogenic effects. Moreover, bacteria containing nitrate reductase can further promote the synthesis of the carcinogen nitrosamine. Under the influence of these carcinogenic and tumor-promoting substances, the gastric mucosa may undergo malignant transformation.

Postoperative scarring and even irritation from non-absorbable sutures may also contribute to the development of remnant stomach cancer.

In summary, gastric surgery alters the normal anatomy and physiological functions of the stomach, exposing it more to carcinogenic and tumor-promoting factors. When the body's immune function is compromised, remnant stomach cancer may occur.

bubble_chart Clinical Manifestations

It is generally similar to typical stomach cancer. Common clinical manifestations of this disease include a sudden onset of symptoms such as loss of appetite, weight loss, occult blood in stool, and persistent pain in the mid-upper abdomen that cannot be relieved by antacids or antispasmodics, occurring more than 10 years after gastrectomy.

Due to the altered normal anatomy and physiological functions of the stomach caused by surgery, X-ray barium meal imaging often misses smaller lesions of fistula disease, resulting in a diagnostic accuracy rate of around 50%.

Gastroscopy with biopsy of suspicious mucosal areas is the primary method for diagnosing this condition, with a diagnostic accuracy rate exceeding 90%.

bubble_chart Treatment Measures

Once diagnosed, surgical exploration should be performed as soon as possible, with every effort made to perform a radical resection.

bubble_chart Prognosis

The prognosis is often poor due to difficulties in early diagnosis. The 5-year survival rate after subtotal or total gastrectomy for gastric cancer is similar to that of gastric cancer patients who have not undergone gastrectomy.