Multidetector-computed tomography attenuation values between the tumor and aortic wall in response to induction therapy for esophageal cancer and its predictive value for aortic invasion.

The objective of this study was to evaluate the multidetector computed tomography (MDCT) attenuation value between the tumor and aorta in response to the induction therapy for esophageal cancer. In advanced esophageal cancer, the main reason for unresectability is the local invasion of the tumor into the aorta or trachea. Despite remarkable advances in diagnostic modalities, pre-operative assessment of pathological response and local tumor extent in esophageal cancer remains difficult. MDCT attenuation values between the tumor and aorta, and the contact angle of the tumor to the aorta (Picus' angle) were retrospectively evaluated in patients with esophageal cancer who underwent induction therapy in terms of predicting the pathological response, aortic invasion and prognosis of esophageal cancer. The induction therapy may increase the tumor-to-aorta distance and decrease the maximum tumor size and Picus' angle. When the tumor-to-aorta cut-off value was set at <1.3 mm, the accuracy of this distance for aortic invasion was 94.6%. In terms of this distance, 14 out of 19 patients with a tumor-to-aorta distance of <1.3 mm prior to the induction therapy had a distance of >1.3 mm following therapy and underwent curative resection. The assessment of the MDCT attenuation value between the esophageal tumor and the aorta is simple and objectively assesses the response to the induction therapy and aortic invasion in esophageal cancer. This method should be applied to predict the response to the induction therapy and to prevent unnecessary surgery in patients with tumors involving the aorta.