Tumors of the stomach are diverse in presentation, symptoms, and prognosis. In this chapter, the authors will first describe the epidemiology, presentation, and management of gastric adenocarcinoma. Subsequently, gastric polyps, mesenchymal tumors (eg, gastrointestinal [GI] stromal tumors), and the rare gastric sarcoma and lymphoma will be discussed.
The first description of stomach cancer documented in Western literature is generally thought to be that of Avicenna (980-1037). Many years later, in 1761, Morgani published a manuscript on malignancies of the stomach. In 1879, Pean was believed to perform the first gastric resection for cancer, followed by Billroth performing the first described pyloric resection in 1881, and Schlatter successfully performing the first total gastrectomy (TG) in 1897. In 1951, McNeer et al recommended a more extensive resection for cancer, including TG with distal pancreatectomy and splenectomy.1
While gastric cancer (GC) is the third leading cause of cancer-related death worldwide, significant differences in its incidence exist across the continents.2 Specifically, a higher incidence is found in Japan and Eastern Asia (approximately 18-25 cases/100,000) than in Europe and North America (approximately 8-10 cases/100,000).3 The incidence of GC in the United States is low as it is currently the 15th most prevalent cancer. In 2015, 24,500 patients were diagnosed with GC, and nearly 10,000 persons are projected to die from GC in 2016. The estimated overall 5-year survival approaches 30%.4
Gastric cancer is a malignant solid organ tumor of older adults (>65 years). The median age of diagnosis is 69 years of age. Similar to other solid organ cancers, older adults are primarily affected.5 In recent years, the incidence of GC has been rising in younger adults (age <50 years). Initially, their outcomes were mistakenly perceived to be worse than older adults. However, a recent large population-based study showed that younger patients were more likely to present with advanced or metastatic disease; however, they have a more favorable stage for stage prognosis than their older counterparts.6
In addition to age, race and ethnicity also impact the presentation, treatment, and prognosis of GC. In the United States, Caucasians typically present with proximal GC, often involving the gastroesophageal junction (GEJ), whereas Asians tend to present with early stage disease, distal tumors, and have a more favorable prognosis. In contrast, African Americans and Hispanics are more likely to present with advanced stage disease and harbor worse outcomes, likely due to a combination of issues related to access to care and multiple morbidities.7,8
Gastric Cancer Risk Factors
The development of GC has been attributed to several risk factors. The most significant appears to be an infection with Helicobacter pylori. This is particularly an issue in developing countries and is more often observed in GC outside the cardia, as supported by a robust meta-analysis of 42 observational studies.9 Diets that contain salt, smoked or poorly preserved foods, nitrates, nitrites, and secondary amines have been shown to contribute to development. In contrast, diets that are rich in raw vegetables, fresh fruits, vitamin ...