The 5-year survival rate in esophageal cancer, although poor, has improved over the past decade. A new review discusses the epidemiologic aspects, pathogenesis, prevention, and therapy of esophageal adenocarcinoma and squamous-cell carcinoma, focusing on recent advances.
In spite of the fact that the ability to detect early-stage esophageal adenocarcinoma has improved, most tumors are found when regional metastasis (in 30% of cases) or distant metastasis (in 40% of cases) has already occurred, at which point the 5-year survival rate declines from 39% in cases of localized disease to 4% in cases with distant metastasis.
• Describe the epidemiology of esophageal cancer.
Esophageal cancer has two main subtypes — esophageal squamous-cell carcinoma and esophageal adenocarcinoma; their precursor lesions are esophageal squamous dysplasia and Barrett’s esophagus, respectively. Although squamous-cell carcinoma accounts for about 90% of cases of esophageal cancer worldwide, the incidence of and mortality rates associated with esophageal adenocarcinoma are rising and have surpassed those of esophageal squamous-cell carcinoma in several regions in North America and Europe. In the United States, more than 18,000 new cases of esophageal cancer and more than 15,000 deaths from esophageal cancer were expected in 2014. Esophageal carcinoma is rare in young people and increases in incidence with age, peaking in the seventh and eighth decades of life. The main risk factors for esophageal adenocarcinoma are gastroesophageal reflux disease, obesity, and cigarette smoking; H. pylori infection is associated with a reduced risk. Cigarette smoking and alcohol consumption constitute the main risk factors for esophageal squamous-cell carcinoma. High intake of red meats, fats, and processed foods is associated with an increased risk of both types of esophageal cancer, whereas high intake of fiber, fresh fruit, and vegetables is associated with a lower risk.
• How do esophageal adenocarcinoma and esophageal squamous-cell carcinoma differ?
Esophageal adenocarcinoma has become the predominant type of esophageal cancer in North America and Europe, while esophageal squamous-cell carcinoma remains the predominant esophageal cancer in Asia, Africa, and South America and among African Americans in North America. Adenocarcinoma is three to four times as common in men as it is in women, whereas the sex distribution is more equal for squamous-cell carcinoma. The endoscopic appearance is also similar, although approximately three quarters of all adenocarcinoma lesions are found in the distal esophagus, whereas squamous-cell carcinoma is more frequent in the proximal to middle esophagus. The overall 5-year survival rate for patients with esophageal adenocarcinoma in the United States is approximately 17%, which is slightly higher than the rate for patients with squamous-cell carcinoma.
Morning Report Questions
Q: What is the typical presentation of a patient with esophageal carcinoma?
A: The clinical presentation is similar between esophageal adenocarcinoma and squamous-cell carcinoma, despite differences in demographic and risk factors. Common clinical presentations include progressive dysphagia, weight loss, and heartburn unresponsive to medical treatment, as well as signs of blood loss. Less common symptoms include hoarseness, cough, and pneumonia related to laryngeal nerve paralysis or invasion of the tracheobronchial tree.
Q: How is adenocarcinoma of the esophagus treated?
A: The introduction of endoscopic mucosal resection with or without ablation has been a major advance in treating not only Barrett’s esophagus with high-grade dysplasia but also adenocarcinoma that is limited to the epithelial portion of the mucosa (category T1a), particularly for small tumors (<2 cm in diameter) that are asymptomatic and noncircumferential. In patients with category T1b tumors that have penetrated the muscularis mucosae and entered the submucosa, the risk of lymph-node spread is as high as 20%, and radical esophagectomy may be the preferred method of treatment, although some treatment centers have expanded the indications for endoscopic therapy to include low-risk submucosal tumors. Locally advanced tumors, defined as category T3N1, are best treated with esophagectomy. The main advance in treating patients who undergo esophagectomy has been the adoption of neoadjuvant treatment. Randomized, controlled trials have shown a survival benefit with neoadjuvant chemoradiotherapy or chemotherapy, as compared with esophagectomy alone, in both types of esophageal carcinoma. Obstructive symptoms related to unresectable disease can be palliated with endoscopic esophageal stenting or high-dose intraluminal brachytherapy.