Jeffrey M. Hardacre

Introduction

The number and types of gastric procedures performed by surgeons-in-training have changed dramatically over time. With the advent of histamine receptor (H₂) blockers and proton pump inhibitors, as well as the discovery of Helicobacter pylori, surgery for peptic ulcer disease has all but disappeared, with the exception of emergency operations for perforation or bleeding. Concomitant with the decrease in the surgical treatment of ulcer disease has been the dramatic decrease in the incidence of gastric cancer in the United States. Opposing these decreasing trends in the surgical treatment of gastric disease has been the explosion in bariatric surgery during last 10 to 15 years.

Even though many more bariatric procedures are performed than standard gastric resections, the ability to perform partial and total gastrectomy must be part of the surgeon’s armamentarium. Currently, about 21,000 new cases of gastric cancer occur each year in the United States.

Principles of Gastric Cancer Treatment

The treatment of gastric cancer depends on a number of factors; the most important are histologic type and location. This chapter focuses on surgical approaches to the treatment of gastric adenocarcinoma.

The treatment of gastric cancer begins with accurate staging. This includes a complete patient history and physical examination, upper gastrointestinal (GI) endoscopy, and computed tomography (CT) of the chest, abdomen, and pelvis. Endoscopic ultrasound may be useful, particularly when neoadjuvant therapy is being considered. Staging laparoscopy is appropriate, because CT-occult disseminated disease may be found in as much as 30% of patients. Palliative resection usually is not needed with current endoscopic interventions.

Surgical resection, including en bloc removal of lymph nodes and adherent organ(s), remains the mainstay of gastric cancer treatment. However, prospective randomized trials have shown that (1) surgery followed by chemoradiation therapy or (2) chemotherapy followed by surgery followed by more chemotherapy are both better than surgery alone. Given the propensity for gastric cancer to spread within the wall of the stomach, gross margins of 5 to 6 cm are usually needed to ensure negative final, histologic margins. The American Joint Committee on Cancer recommends that at least 16 lymph nodes be assessed for staging.

Surgical Approach for Gastrectomy

The abdomen is explored to evaluate for metastatic disease, usually through an upper midline incision, although some surgeons prefer a chevron incision. Laparoscopic-assisted approaches to gastric resection are increasingly used. Figure 8-1 shows the stomach in situ with its relationship to surrounding structures. Figures 8-1, 8-2, and 8-3, A, show the arterial and venous anatomy pertinent to gastric resection.

Once disseminated disease is excluded, dissection begins with mobilization of the stomach. The lesser sac is entered by taking the omentum off the transverse colon, keeping the omentum with the stomach. This approach provides wide exposure of the posterior aspect of the stomach and lesser sac (Figs. 8-2 and 8-3) and allows the surgeon to assess for any posterior invasion by the tumor.

Next, the lesser omentum is divided, keeping the lymphatic tissue with the stomach. Care must be taken to look for a replaced left hepatic artery coming off the left gastric artery.

At this point, an assessment is made as to the extent of resection that will be required. Distal tumors (Fig. 8-4, A) are treated with distal/subtotal gastrectomy, and proximal tumors (Figure 8-4, B with total gastrectomy. Achieving negative margins for tumors along the lesser curvature of the stomach is more difficult than for tumors along the greater curvature of the stomach; thus, lesser curve tumors more often require total gastrectomy.

The duodenum is divided with a surgical stapler. The duodenal stump may be left as a simple staple line, or it may be oversewn by using simple Lembert sutures or by burying the staple line and suturing the duodenum to the capsule of the pancreas. The left gastric artery is taken at its origin; in some patients, this is best done along the lesser curvature of the stomach or with the stomach retracted cranially (see Fig. 8-2). Proximal transection is achieved with multiple firings of the surgical stapler. If a total gastrectomy is performed and a circular-stapler anastomosis is planned, the purse-string staple device may be used for the proximal transection. Both proximal and distal margins are assessed through frozen section, and further resection is undertaken if necessary.

While performing the resection, the surgeon must be cognizant not only of margins but also of the extent of lymphadenectomy. Figure 8-3 highlights the 16 lymph node basins. A D1 lymphadenectomy refers to removal of the perigastric lymph nodes. A D2 lymphadenectomy adds removal of nodes along the left gastric, celiac, and splenic arteries, as well as the nodes in the splenic hilum. A D3 lymphadenectomy adds removal of nodes in the hepatic portal (porta hepatis) and the periaortic regions.

Controversy persists regarding the appropriate extent of lymphadenectomy, with the competing issues being appropriate staging and survival benefit versus increased surgical morbidity and mortality. Two Western prospective randomized trials have shown no survival benefit when doing a D2 versus a D1 lymphadenectomy, while having greater morbidity associated with the D2 dissection (see Suggested Readings). Despite this, treatment guidelines published by the National Comprehensive Cancer Network recommend a D2 versus a D1 lymphadenectomy.

Reconstruction after a distal gastrectomy is usually accomplished with a Billroth II gastrojejunostomy (Fig. 8-4, C). This instrument is generally favored over a Billroth I (gastroduodenostomy) reconstruction because of concerns regarding anastomotic tension as well as potential tumor recurrence. Reconstruction after a total gastrectomy may be performed with either a Roux-en-Y esophagojejunostomy or a loop esophagojejunostomy with a distal enteroenterostomy, with the hope of diverting bile and pancreatic juice from the esophagus. Some favor formation of a jejunal pouch as a “neostomach,” but this has shown no clear benefit. For either a distal or a total resection, the jejunum may be brought up for reconstruction in an antecolic or a retrocolic manner. Drains are not routinely placed after a gastrectomy.

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