Background and study aims: Measuring the response of esophageal cancer to combined chemotherapy and radiotherapy is difficult. Initial results using ultrasonography have been contradictory. The purpose of this study was to correlate the endoscopic ultrasonography (EUS) findings after preoperative chemoradiotherapy with the histology of the resected specimens, and to assess the accuracy of EUS in predicting the response to treatment.
Patients and methods: From October 1991 to February 1995, 32 patients with esophageal cancer staged as T3 or T4 on EUS were treated by chemoradiotherapy, followed by surgical resection. There were 28 men and four women, with a mean age of 54 years (range 38-70 years). In 25 cases, the diagnosis was squamous-cell carcinoma, and in seven cases it was adenocarcinoma. EUS was carried out using a curved-array ultrasonic transducer (Pentax FG-32 UA). After two courses of chemoradiotherapy, the wall involvement was classified using the following modified post-chemoradiotherapy classification: T0, complete restitution of wall layers; Tw, echo-poor nodules located in the submucosa or muscularis propria, but with wall layers discernible; T2, echo-poor wall thickening without distinguishable layers, but not infiltrating beyond the fifth hyperechoic layer; T3, thickened hypoechoic or heterogeneous wall, no distinguishable layers, infiltrating beyond the fifth hyperechoic layer; T4: a hypoechoic or heterogeneous mass in contact with a mediastinal structure.
Results: Using this post-chemoradiotherapy classification, the sensitivity, specificity, and accuracy of EUS in detecting residual tumor (T0 + Tw versus T2, T3, and T4) were 91.3%, 77.7%, and 77.7%, respectively. The accuracy of EUS, endoscopic, and CT criteria in assessing the parietal response was 81.2%, 56.2%, and 59.3%, respectively.
Conclusion: Complete restoration of the esophageal wall (T0) and Tw stage corresponded to disease-free histology in 78% of cases, and corresponded in all cases either to disease-free esophageal wall or to microscopic tumor residues in the mucosa. No conclusions could be drawn in the other categories (T2-T4), but residual tumor was detected in 87% of cases.