The natural history of Barrett's esophagus, particularly the prevalence and incidence of malignant changes in it, remains controversial. Furthermore the prognosis of surgically treated patients with carcinoma in Barrett's esophagus has not been elucidated fully. To examine these and other issues, the records of 65 patients with carcinoma in Barrett's esophagus presenting at the Lahey Clinic Medical Center from January 1973 to January 1989 were reviewed. During this period, 241 patients with documented Barrett's esophagus were seen, for a prevalence of carcinoma of 27%. Adenocarcinoma in Barrett's esophagus accounted for 30% of the surgically treated carcinomas of the thoracic esophagus during this period. All but four of these patients were men. Symptoms of chronic reflux were present in less than one half of the patients and dysphagia was often the presenting symptom. In eight patients the carcinoma was discovered on routine surveillance endoscopy, and in four patients progression of disease from benign columnar epithelium to dysplasia to carcinoma was documented. Tumors developed in six patients who had undergone previous antireflux surgery, and in four other patients a second carcinoma developed in residual Barrett's epithelium after a previous resection. Of the 65 patients, 61 (94%) were considered to have operable disease, all of whom underwent resection. Two patients (3.3%) died within 30 days of operation. The resected specimens were staged as follows: stage 0, 4; stage I, 10; stage II, 17; stage III, 25; stage IV, 4. Of the resected specimens, 73% showed areas of dysplasia adjacent to the tumor. The overall adjusted actuarial 5-year survival rate was 23.7%. The 3-year survival rate was 100% for patients with stage 0 carcinoma, 85.7% for patients with stage I carcinoma, 53.6% for patients with stage IIA carcinoma, 45% for patients with stage IIB carcinoma, 25.2% for patients with stage III carcinoma, and 0% for patients with stage IV carcinoma. The premalignant nature of Barrett's esophagus requires endoscopic surveillance to detect early carcinoma because symptoms often occur late or are absent. Antireflux surgery does not protect against the development of carcinoma. All of the Barrett's epithelium must be resected because a second carcinoma may develop in residual columnar epithelium. Severe dysplasia should be considered an indication for resection. Although operability and resectability rates are high, long-term survival is not. Early detection is mandatory if long-term survival is to be achieved.