Chapter 087. Gastrointestinal Tract Cancer (Part 2)

Clinical Features About 10% of esophageal cancers occur in the upper third of the esophagus (cervical esophagus), 35% in the middle third, and 55% in the lower third. Squamous cell carcinomas and adenocarcinomas cannot be distinguished radiographically or endoscopically.Progressive dysphagia and weight loss of short duration are the initial symptoms in the vast majority of patients. Dysphagia initially occurs with solid foods and gradually progresses to include semisolids and liquids. By the time these symptoms develop, the disease is usually incurable, since difficulty in swallowing does not occur until 60% of the esophageal circumference isinfiltrated with cancer. Dysphagia may...
Nội dung trích xuất từ tài liệu:
Chapter 087. Gastrointestinal Tract Cancer (Part 2) Chapter 087. Gastrointestinal Tract Cancer (Part 2) Clinical Features About 10% of esophageal cancers occur in the upper third of the esophagus(cervical esophagus), 35% in the middle third, and 55% in the lower third.Squamous cell carcinomas and adenocarcinomas cannot be distinguishedradiographically or endoscopically. Progressive dysphagia and weight loss of short duration are the initialsymptoms in the vast majority of patients. Dysphagia initially occurs with solidfoods and gradually progresses to include semisolids and liquids. By the timethese symptoms develop, the disease is usually incurable, since difficulty inswallowing does not occur until >60% of the esophageal circumference isinfiltrated with cancer. Dysphagia may be associated with pain on swallowing(odynophagia), pain radiating to the chest and/or back, regurgitation or vomiting,and aspiration pneumonia. The disease most commonly spreads to adjacent andsupraclavicular lymph nodes, liver, lungs, pleura, and bone. Tracheoesophagealfistulas may develop as the disease advances, leading to severe suffering. As withother squamous cell carcinomas, hypercalcemia may occur in the absence ofosseous metastases, probably from parathormone-related peptide secreted bytumor cells (Chap. 96). Diagnosis Attempts at endoscopic and cytologic screening for carcinoma in patientswith Barretts esophagus, while effective as a means of detecting high-gradedysplasia, have not yet been shown to improve the prognosis in individuals foundto have a carcinoma. Routine contrast radiographs effectively identify esophageallesions large enough to cause symptoms. In contrast to benign esophagealleiomyomas, which result in esophageal narrowing with preservation of a normalmucosal pattern, esophageal carcinomas show ragged, ulcerating changes in themucosa in association with deeper infiltration, producing a picture resemblingachalasia. Smaller, potentially resectable tumors are often poorly visualizeddespite technically adequate esophagograms. Because of this, esophagoscopyshould be performed in all patients suspected of having an esophagealabnormality, to visualize the tumor and to obtain histopathologic confirmation ofthe diagnosis. Because the population of persons at risk for squamous cellcarcinoma of the esophagus (i.e., smokers and drinkers) also has a high rate ofcancers of the lung and the head and neck region, endoscopic inspection of thelarynx, trachea, and bronchi should also be done. A thorough examination of thefundus of the stomach (by retroflexing the endoscope) is imperative as well.Endoscopic biopsies of esophageal tumors fail to recover malignant tissue in one-third of cases because the biopsy forceps cannot penetrate deeply enough throughnormal mucosa pushed in front of the carcinoma. Cytologic examination of tumorbrushings complements standard biopsies and should be performed routinely. Theextent of tumor spread to the mediastinum and para-aortic lymph nodes should beassessed by CT scans of the chest and abdomen and by endoscopic ultrasound.Positron emission tomography scanning provides a useful assessment ofresectability, offering accurate information regarding spread to mediastinal lymphnodes. Esophageal Cancer: Treatment The prognosis for patients with esophageal carcinoma is poor. Fewer than5% of patients survive 5 years after the diagnosis; thus, management focuses onsymptom control. Surgical resection of all gross tumor (i.e., total resection) isfeasible in only 45% of cases, with residual tumor cells frequently present at theresection margins. Such esophagectomies have been associated with apostoperative mortality rate of 5–10% due to anastomotic fistulas, subphrenicabscesses, and respiratory complications. About 20% of patients who survive atotal resection live 5 years. The efficacy of primary radiation therapy (5500–6000cGy) for squamous cell carcinomas is similar to that of radical surgery, sparingpatients perioperative morbidity but often resulting in less satisfactory palliation ofobstructive symptoms. The evaluation of chemotherapeutic agents in patients withesophageal carcinoma has been hampered by ambiguity in the definition ofresponse and the debilitated physical condition of many treated individuals.Nonetheless, significant reductions in the size of measurable tumor masses havebeen reported in 15–25% of patients given single-agent treatment and in 30–60%of patients treated with drug combinations that include cisplatin. Combinationchemotherapy and radiation therapy as the initial therapeutic approach, eitheralone or followed by an attempt at operative resection, seems to be beneficial.When administered al ...