Gastric surgery may be indicated for a wide variety of benign or malignant conditions. In the past, the most frequent reason for an operation on the stomach was peptic ulcer disease. With the advent of proton-pump inhibitors and therapy for H. pylori medical management has largely replaced surgical treatment for this disease. Nevertheless, patients still occasionally present with complications of ulcer disease requiring surgery such as free air from a perforation (Fig. 6.1), bleeding ulcer, or pyloric stricture. In patients who have never tried pharmacologic therapy, it is best to simply address the surgical emergency and initiate proton-pump therapy postoperatively. However, patients who are truly refractory to medical therapy may benefit from an antrectomy and vagotomy to decrease acid production.

The object of surgical therapy of peptic ulcer disease is to block the two agents that most stimulate acid secretion by the parietal cell: gastrin and acetylcholine. The antrum of the stomach is the region that contains G-cells that secrete gastrin into the systemic circulation; the goal of antiacid surgery is to resect the antrum, and thus eliminate the source of gastrin. The other mechanism driving acid secretion by the parietal cells is acetylcholine, which is released via vagal nerve stimulation. A truncal vagotomy involves ligating the main right and left vagal trunks that lie along the esophagus. The combination of antrectomy and vagotomy thereby dramatically reduces acid production and allows healing of the gastric or duodenal ulcer.

It is important to keep in mind that not every ulcer is acid related. Atypical ulcers, such as those located in the proximal stomach, or non-healing ulcers, should raise suspicion for an underlying malignancy and should be biopsied for further evaluation. Indeed, gastric adenocarcinoma is now the leading indication for gastrectomy (Fig. 6.2). Major risk factors for the development of gastric cancer include Helicobacter pylori infection, Asian ethnicity, smoking, a diet high in cured meats, and pernicious anemia. Interestingly, a history of prior partial gastrectomy also confers a greater risk for gastric adenocarcinoma, known as gastric remnant cancer. Gastric cancer is usually insidious in onset, and patients do not become symptomatic until the disease is relatively advanced.

Once a clinical suspicion of cancer exits, upper endoscopy and biopsy are performed for diagnosis. Next, a CT scan is obtained to evaluate for metastatic disease, most often found in the liver. Gastric cancer also has a predilection for early peritoneal dissemination, and a diagnostic laparoscopy should be performed to rule out carcinomatosis. If no metastases are present, then patients are candidates for surgical resection. Prior to surgery, many centers include endoscopic ultrasound (EUS), in their staging work-up. If the tumor is deep (T stage ≥3) or there is evidence of nodal involvement (N stage ≥1), neoadjuvant chemotherapy is administered prior to resection.

Gastric adenocarcinomas have a tendency for submucosal spread that is always more extensive than suggested by the gross size of the tumor. Therefore surgical resection must include 6 cm margins beyond the visible extent of the tumor. Interestingly, margins need not extend past the esophagus or the pylorus, since these sphincters act as natural barriers to tumor extension. A lymph node dissection should be included in the procedure, although the extent of lymphadenectomy required is somewhat controversial. While the literature on the subject is mixed, many centers advocate a modified D2 lymphadenectomy. This dissection includes resection of the perigastric nodes as well as a dissection of the lymph nodes along the celiac trunk, common hepatic artery, left gastric artery, and splenic artery.

Less common malignancies of the stomach include gastrointestinal stromal tumors, gastric carcinoids, and gastric lymphoma. Gastrointestinal stromal tumors (GIST) are a type of sarcoma that can occur anywhere along the GI tract, but are most commonly found in the stomach. Unlike adenocarcinoma which arises from the gastric mucosa, GISTs are derived from the interstitial cells of Cajal, located in the submucosa. As a result, GISTs have a distinct appearance: they are typically exophytic round lesions with a smooth mucosal surface (Fig. 6.3). An endoscopic ultrasound showing that the lesion originates in the submucosa is sufficient for diagnosis. Biopsy is not necessary prior to surgery, but if performed will demonstrate spindle cells. Unlike gastric adenocarcinoma, GISTs are well-encapsulated require neither extensive margins nor a lymph node dissection. However, even after complete resection, GISTs may recur locally or may present with liver or lung metastases.