ENDOSCOPIC ULTRASONOGRAPHY FOR ASSESSMENT OF THE RESPONSE TO COMBINEDRADIATION-THERAPY AND CHEMOTHERAPY IN PATIENTS WITH ESOPHAGEAL CANCER

Background and Study Aims: Measuring the response of esophageal cancer to combined chemotherapy and radiotherapy is difficult. Initial resul ts using ultrasonography have been contradictory. The purpose of this study was to correlate the endoscopic ultrasonography (EUS) findings a fter preoperative chemoradiotherapy with the histology of the resected specimens, and to assess the accuracy of EUS in predicting the respon se to treatment. Patients and Methods: From October 1991 to February 1 995, 32 patients with esophageal cancer staged as T3 or T4 on EUS were treated by chemoradiotherapy, followed by surgical resection. There w ere 28 men and four women, with a mean age of 54 years (range 38-70 ye ars). In 25 cases, the diagnosis was squamous-cell carcinoma, and in s even cases it was adenocarcinoma. EUS was carried out using a curved-a rray ultrasonic transducer (Pentax FG-32 UA). After two courses of che moradiotherapy, the wall involvement was classified using the followin g modified post-chemoradiotherapy classification: T0, complete restitu tion of wall layers; Tw, echo-poor nodules located in the submucosa or muscularis propria, but with wall layers discernible; T2, echo-poor w all thickening without distinguishable layers, but not infiltrating be yond the fifth hyperechoic layer; T3, thickened hypoechoic or heteroge neous wall, no distinguishable layers, infiltrating beyond the fifth h yperechoic layer; T4: a hypoechoic or heterogeneous mass in contact wi th 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 c riteria in assessing the parietal response was 81.2%, 5P.2%, and 59.3% , respectively. Conclusion: Complete restoration of the esophageal wal l (T0) and Tw stage corresponded to disease-free histology in 78% of c ases, and corresponded in all cases either to disease-free esophageal wall or to microscopic tumor residues in the mucosa, No conclusions co uld be drawn in the other categories (T2-T4), but residual tumor was d etected in 87% of cases.