Adenocarcinomas of esophagogastric junction: multi-detector row CT to evaluate early response to neoadjuvant chemotherapy.

PURPOSE

To prospectively evaluate multi-detector row computed tomography (CT) in the assessment of early response during neoadjuvant chemotherapy for adenocarcinoma of the esophagogastric junction (AEG).

MATERIALS AND METHODS

The study protocol was approved by the local ethics committee. Written informed consent was obtained from all patients. Thirty-one patients with an AEG (stage T3 N0/1 M0 or T4 N0/1 M0) were examined with multi-detector row CT before and 2 weeks after the initiation of chemotherapy. There were seven women and 24 men with a mean age of 62 years +/- 8.1 (standard deviation). The maximal transverse tumor diameter was measured and tumor volumetry was performed by three independent readers. The resulting changes were correlated with the histopathologic grade of regression in 21 patients. The differentiation of responders from nonresponders was assessed with receiver operating characteristic analysis in these 21 patients. Interobserver variability was determined in all 31 patients with the Spearman rank correlation. Survival without disease progression was estimated in all patients according to the Kaplan-Meier method. Statistical comparisons between different groups of patients were performed with the log-rank test.

RESULTS

The interobserver variability for the diameter measurements (R = 0.13-0.20) was higher than that for the volumetric measurements (R = 0.70-0.82). The correlation of histopathologic grades of regression with changes in diameter was not statistically significant for the three readers, whereas the correlation of volume changes with histopathologic grades of regression was statistically significant for two of the three readers (P = .01, .05, and .08). Results of receiver operating characteristic analysis revealed an optimal cutoff level for tumor volumetry at a reduction of volume of 14.8%, which resulted in a sensitivity of 100% (six of six patients) and a specificity of 53% (eight of 15 patients). Although the probability of progression was higher in the nonresponder group than in the responder group (61% vs 40%, respectively), the differences were not statistically significant.

CONCLUSION

Tumor volumetry based on multi-detector row CT can help predict early response to treatment 2 weeks after the initiation of neoadjuvant chemotherapy in patients with AEG; however, the classic approach of tumor diameter measurement failed to show significant correlation with histopathologic tumor regression.