Cancers of the stomach (gastric) and esophagus are a major public health concern. Other terms for these cancers include gastroesophageal cancer or esophagogastric cancer. About 13,000 men and 8,000 women will be diagnosed with gastric or esophageal cancer yearly in the United States. Though the incidence of certain types of gastric cancers has decreased, cancers of the gastroesophageal (GE) junction and lower esophagus are increasing in frequency.
The innermost layers of the esophagus and stomach are the site where esophageal and gastric cancers most often begin. Cancers affecting the esophagus are usually either “squamous cell carcinoma" (SCC) or “adenocarcinoma”, which differ in a number of ways. Most SCCs develop in the upper or middle esophageal region and smoking and alcohol use are the major risk factors. Adenocarcinomas of the esophagus tend to start in the distal esophagus or GE junction. For esophageal or GE junction adenocarcinomas, the predominant risk factors are obesity, smoking, having a disorder called “Barrett’s esophagus”, or gastroesophageal reflux disease (GERD). Cancer arising in the stomach is mainly adenocarcinoma. Infection in the stomach by a certain bacteria called Helicobacter pylori is a primary risk factor for developing this disease.
Stomach and esophageal cancers tend to develop slowly over many years. Precancerous changes that occur in the inner mucosal layer of the stomach or esophagus rarely cause symptoms, and therefore frequently go undetected. Once symptoms develop and the cancer has been identified, esophagogastric cancers can be removed using surgery as the primary method of treatment. However, when these cancers spread from the area where they initially develop (the “primary” tumor), the major focus of treatment becomes chemotherapy with or without radiation therapy. There are three different ways tumors can spread. First, the primary tumor can grow and invade the other layers of the stomach or esophagus and invade normal tissue surrounding the tumor. Second, cancer cells from the tumor can enter the lymph system and travel through lymph vessels to distant parts of the body. Third, cancer cells from the tumor can get into the bloodstream, and travel to other places in the body. In these distant places, the esophagogastric cancer cells can cause secondary tumors (metastases) to grow. To find out whether the cancer is limited to the primary site or whether the cancer has begun to spread, the lymph nodes near the primary tumor are often evaluated through biopsy. Several kinds of imaging may also be performed in diagnosing gastric and esophageal cancers to “stage” the disease. These include chest x-ray, MRI, CT scan, and PET scan techniques.
Testing for the presence of a specific cancer-related protein called HER2 (ERBB2) in the tumor specimen is an additional evaluation that is performed in esophagogastric cancer. The presence of HER2-expression in esophagogastric cancer has important therapeutic implications. There are also trials being conducted for patients with MET-amplified or EGFR-amplified tumors.
Sources: National Cancer Institute, 2013; The American Cancer Society, 2013; Partners Clinical Handbook, 2013
Cancers of the stomach and esophagus, also collectively referred to as gastroesophageal or esophagogastric cancer, represent a major public health concern. Gastric cancer is the fourth most commonly diagnosed cancer and the second most common cause of cancer death worldwide. Gastric cancer incidence varies throughout the world, with Japan and Korea having the highest incidences. According to the American Cancer Society (ACS), 21,600 new cases and 10,990 deaths are estimated for 2013 in the United States. For esophageal cancers, the ACS estimates 17,990 new esophageal cancers diagnosed in the United States during 2013, resulting in about 15,210 deaths (12,220 men and 2,990 women).
Most cancers involving the esophagus or stomach are either squamous cell (SCC) or adenocarcinoma. Squamous cell cancers were formerly the predominant histology for esophageal cancers. However, since the 1970s, the frequency of adenocarcinomas of the esophagus, gastroesophageal junction (GEJ), and gastric cardia has increased dramatically. Esophageal SCCs and adenocarcinomas of the distal esophagus, GEJ, or gastric cardia differ in a number of ways. Most SCCs develop in the “middle esophageal” region, and smoking and alcohol use are the major risk factors. For adenocarcinomas, the predominant risk factors are obesity, smoking, and “Barrett’s esophagus” with associated intestinal metaplasia, or gastroesophageal reflux disease (GERD). Meanwhile, risk factors associated with more distal gastric adenocarcinomas include 1) Helicobacter pylori infection, 2) a diet low in fruits and vegetables, 3) a diet high in salted, smoked, or preserved foods, 3) chronic atrophic gastritis, and 4) pernicious anemia, among other risk factors.
Gastric and esophageal cancers tend to develop slowly over many years in the inner mucosal layer of the stomach or esophagus. These early changes rarely cause symptoms, and therefore frequently go undetected. As esophageal and gastric cancers become more advanced, symptoms can include discomfort or pain in the stomach area, difficulty swallowing, nausea and vomiting, weight loss, feeling full or bloated after a small meal, vomiting blood, or having blood in the stool. Once symptoms bring a patient to medical attention, endoscopic biopsy is routinely used to diagnose the cancer. Staging workup should include radiographic imaging, such as CT with intravenous contrast, with or without accompanying PET scan. In the case of esophageal cancer, endoscopic ultrasound (EUS) with fine-needle biopsy of suspicious lymph nodes may be used to more accurately stage locoregional disease. The staging workup of gastric cancers may involve diagnostic laparoscopy to rule out occult metastatic disease.
Treatment options for esophageal and gastric cancers depend on the size and location of the tumor, the stage of disease, and overall health of the patient. In the absence of distant spread of disease, a multi-disciplinary approach involving surgery, radiation and chemotherapy is required. Except in cases of very early-stage disease, neoadjuvant and peri-operative approaches involving chemotherapy with or without radiation should be considered in order to optimize the chances of curative resection. In cases of gastric or GEJ cancers where surgery is pursued first, adjuvant therapy may be appropriate.
Metastatic esophageal and gastric adenocarcinomas are treated similarly with systemic chemotherapy. Despite a variety of chemotherapeutic regimens that are available, the median survival for metastatic esophagogastric cancer patients is less than 1 year. Therefore, there has been a growing interest in the molecular features of these diseases, with the expectation that activating molecular lesions may be targets for novel therapeutic agents. For patients with HER2-positive tumors, targeted therapy is now an option. There are also trials being conducted for patients with MET-amplified or EGFR-amplified tumors.
Source: National Cancer Institute, 2013; The American Cancer Society, 2013; Up-To-Date, 2013
Cancer research and treatments are constantly changing. Knowing the gene associated with your cancer can help doctors determine the most appropriate direction of care for you. To learn how you can find out more about genetic testing please visit http://www.massgeneral.org/cancer/news/faq.aspx
or contact the Cancer Center.
The mutation of a gene provides clinicians with a very detailed look at your cancer. Knowing this information could change the course of your care. To learn how you can find out more about genetic testing please visit http://www.massgeneral.org/cancer/news/faq.aspx
or contact the Cancer Center.