Background: Endoscopic ultrasound (EUS) is considered a gold standard in the initial staging of esophageal cancer. There is an ongoing debate whether EUS is useful for tumor staging after neoadjuvant chemotherapy (NAC).
Methods: Ninety-five patients with esophageal cancer were retrospectively analyzed. In 45 patients, EUS was performed prior to and after NAC, while 50 patients had no induction therapy. Histological correlation through surgery was available. uT/uN classifications were compared to pT/pN stages. Statistical analysis included calculation of sensitivity, specificity, and accuracy rates. Agreement between endosonography and T staging was assessed with Cohen's kappa statistics.
Results: For those patients with prior NAC, overall accuracy of yuT and yuN classification was 29 and 62%, respectively. Sensitivity, specificity, and accuracy rates for local tumor extension after NAC were as follows (%): T1: -/97/84, T2: 13/76/53, T3:86/29/46, T4:20/100/91, T1/2: 27/83/56, T3/4: 89/31/56. Cohen's kappa indicated poor agreement (kappa = 0.129) between yuT classification and ypT stage. Relative to positive lymph node detection, sensitivity and specificity were 100 and 6%, respectively (kappa = 0.06). T stage was overstaged in 23 (51%) and understaged in seven (16%) patients.
Conclusion: EUS is an unreliable tool for staging esophageal cancer after NAC. Overstaging of the T stage is common after NAC.