BACKGROUND AND EPIDEMIOLOGY
Gastric cancer is a global health problem with an estimated one million new cases diagnosed a year.1 It is the third and fifth leading cause of cancer-related deaths worldwide in men and women, respectively.2 It is the fourth leading cause of cancer-related death in the United States, accounting for approximately 11,000 deaths a year.2 The majority of new cases are occurring in developing countries in Asia, South America, and Eastern Europe, with almost half of all new cases diagnosed in China alone.3 Although the overall incidence of gastric cancer has not increased in the United States, tumors located at the gastroesophageal (GE) junction have increased.2
Gastric cancer subtypes in the Eastern countries differ when compared to the United States and other Western countries. Generally, the United States and other Western countries develop a higher incidence of diffuse-type histology and tumors are more commonly located at or around the GE junction.4 The relative distinction has been postulated to reflect cultural, behavioral, and dietary patterns.
Racial and gender variation has been observed in gastric cancer. In the United States, white patients have approximately half the risk for gastric cancer in age-matched minority patients, including blacks, Hispanics, and Asian/Pacific Islanders.5 Moreover, white patients are less likely to die from disease compared to other minorities. For example, black patients are 2.2 times as likely to die from gastric cancer compared to white patients. Similar trends are seen for other minorities including Hispanics and Asian/Pacific Islanders who have 1.8 and 2.2 higher mortality rates compared to whites, respectively.5 Finally, the incidence of gastric cancer in males is double the incidence in women, and men have mortality rates twice as high as women.5
The diagnosis of gastric cancer is established by standard upper endoscopy. With this tool, tumor location can be determined and tissue obtained for diagnosis. Endoscopic ultrasound (EUS) offers the additional benefit of assessing tumor depth of invasion and potentially nodal status, although the sensitivity and specificity are operator dependent. EUS has an accuracy of 65% to 92% for T staging and approximately 50% for N staging.6,7 Patients will undergo a computerized tomography (CT) scan of the abdomen and pelvis to improve preoperative clinical staging. Patients then undergo staging laparoscopy to detect occult peritoneal metastases. A review from our institution at Memorial Sloan Kettering Cancer Center of 657 patients with gastric adenocarcinoma without definitive metastatic disease on CT imaging who underwent staging laparoscopy found that 31% of those patients had occult peritoneal metastases.8 Patients without nodal metastases (N0) and early T staging (T1 or T2) on EUS are considered early-stage gastric cancer and may not need staging laparoscopy as the risk of peritoneal metastases is relatively low (4%).9 Some patients may also undergo positron emission tomography (PET) with 18-flurodeoxyglucose (FDG) for staging gastric cancer; ...