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Prognonsis and Treatment

Overall, the 5-year survival rate in the USA from gastric cancer is 27% (compared with 64% for colon cancer). 4 The TNM classification is used to stratify disease into 4 clinical stages (I through IV) to predict prognosis in patients treated with gastrectomy (see Table 54-4). The survival data from Japanese studies are generally superior to those seen in Western countries, perhaps because of the preference in Japan for extended lymphadenectomy or because of less “understaging” than is found in Western countries.351 There are data to suggest that large tumor size (>5 cm) may be independently associated with worse survival, independent of nodal status or overall tumor stage.352

 

Surgery

Surgical resection remains the primary curative treatment for gastric cancer. In addition, surgical resection often provides the most effective palliation of symptoms, particularly those of obstruction. In some cases, surgery is required for diagnosis, as in cases of nonhealing gastric ulcers with negative biopsy results and persistent pyloric outlet obstruction suggesting an antral carcinoma. Surgery should be attempted in most cases of gastric cancer. However, in the presence of extensive involvement of diffuse-type cancer (or linitis plastica), bulky metastatic disease, retroperitoneal invasion, or peritoneal carcinomatosis, or if the patient has severe comorbid illnesses, the prognosis may be sufficiently poor to make the value of resection questionable.

Surgery, and laparoscopy in particular, can be useful in the staging of cancer. Laparoscopy can help identify primary tumor resectability, peritoneal deposits, and appropriate candidates for neoadjuvant therapy. Laparoscopic peritoneal lavage has been used to detect intraperitoneal free cancer cells. A positive peritoneal lavage correlates significantly with eventual development of overt peritoneal metastases.353

In general, total gastrectomy is performed for proximal gastric tumors and for diffuse gastric cancer, and partial gastrectomy is reserved for tumors in the distal stomach. Large, randomized multicenter trials in France and Italy comparing subtotal with total gastrectomy for adenocarcinoma of the antrum found no differences in 5-year survival rates or operative mortality.354,355 Some centers have argued for performing a complete splenectomy with gastrectomy. However, several retrospective and prospective studies found that concurrent splenectomy increased morbidity and had either no effect on or worsened survival.356,357

The extent of lymphadenectomy accompanying the gastrectomy has been a subject of debate for many years. The Japanese advocate a more extensive lymph node dissection (D2 resection) than their Western counterparts (D1 resection) and have higher published survival rates. A D2 resection entails resection of the nodes of the celiac axis and the hepatoduodenal ligament in addition to the perigastric lymph nodes taken in a D1 procedure. The differences in reported survival rates may reflect the fact that the Japanese have a much higher incidence of early gastric cancer, and the more extensive lymph node dissection performed in Japan may find more positive lymph nodes, making survival rates of Japanese patients with N0 staging appear to be higher than those of their potentially “understaged” Western counterparts. A large multicenter randomized trial from the Netherlands reported no significant improvement in 5-year survival and more postoperative deaths and complications with D2 lymphadenectomy than with the more conservative D1 lymphadenectomy.358 In a subsequent 15-year follow-up of these patients, the investigators reported no significant difference in overall survival, although there was significantly reduced gastric cancer-related mortality in the D2 resection arm (37% vs. 48% in the D1 arm).359 A British randomized trial of 400 patients likewise showed no benefit from more extensive surgery: 5-year survival rates were 35% for D1 resection and 33% for D2 resection.356 At present, data are insufficient to support extended lymph node resection in centers outside Japan. To prevent “understaging,” the current recommendation is a minimum D1 lymphadenectomy with removal of at least 15 nodes.360