Stomach and Abdominal Wall

Abstract

Gastric cancer is the fourth most common cancer and accounts for approximately 600,000 new cases each year worldwide. Seventy-five percent of gastric cancer occurs in developing countries in the regions of Eastern Europe and East Asia. The incidence of gastric cancer in the United States has been decreasing over the last 60 years, and in 2007, there were 21,260 new cases diagnosed. Almost two-thirds of these patients will die of their disease. Ninety-five percent of gastric carcinomas are adenocarcinomas. The remaining 5% are lymphoma, carcinoids, and gastrointestinal stromal tumors (GIST). Factors associated with an increased risk of gastric adenocarcinoma include diets high in salt and smoked foods, male gender, black race, and low socioeconomic class. Helicobacter pylori, a gram negative bacteria, is now known to play a central role in the pathogenesis of gastric cancer and is considered to be a carcinogen by the International Agency for Research on Cancer at the World Health Organization. Chronic long-term infection of the gastric mucosa with h pylori seems to be a major promoter of gastric carcinoma. In developing countries, 80–90% of children are infected with h pylori. Currently in the United States, the problems of h pylori infections have been steadily declining, probably because of smaller family size, better hygiene, and increased use of antibiotics during childhood. The decline in h pylori has probably contributed to the downward trend of gastric adenocarcinoma. Along with a decrease in gastric cancer, there has also been a steady decrease in mortality from gastric carcinoma in the United States.

Unfortunately, gastric adenocarcinoma usually presents with very nonspecific symptoms of weight loss, nausea, fatigue, and as the disease progresses, anorexia and vomiting. At the time of diagnosis in the United States, most patients either have locally advanced or metastatic disease. The distribution of disease or presentation is 24% with localized disease, 32% with node positive disease, and 32% with metastatic disease. Endoscopy with biopsy, CT, and endoscopic ultrasound, all aid in the diagnosis and staging of gastric carcinoma. Combined CT/PET is also extremely helpful in ruling out patients with metastatic disease. The overall accuracy of PET/CT is superior to either modality alone. Because of the limitations of CT and PET in the evaluation of peritoneal disease, diagnostic laparoscopy should be done before an open procedure in asymptomatic patients to avoid an unnecessary laparotomy. Several prospective studies have shown that laparoscopy will detect metastatic disease in 24–32% of patients thought to be resectable by standard imaging criteria. Multivari-ate analysis revealed that patients with diffuse gastric disease and lymphadenopathy, defined as nodes greater than 1 cm, were significant, are independent predictors for M1 disease. If a palliative resection and/or bypass are/is already planned, then lap-aroscopic staging is not necessary. In addition, laparoscopy can be a useful staging tool before neoadjuvant therapy is initiated.