Assessment of transendoscopic miniature ultrasonic probe for chemoradiotherapy outcome in patients with locally advanced esophageal cancer

Background: Assessment of the response of esophageal cancer to chemoradiotherapy is difficult. We investigated the value of a transendoscopic miniature ultrasonic probe (USP) in assessing response to chemoradiotherapy in patients with locally advanced esophageal cancer. Methods: A total of 33 patients were entered in this prospective study. Response to treatment was evaluated according to World Health Organization criteria. According to the sonographic image, complete response (CR) of the primary lesion was divided into two subcategories: confirmed CR (cCR) and unconfirmed CR (uCR). Results: Initial sonographic criteria for evaluating tumor depth and lymph nodes in the 33 patients before therapy showed two cases of T2N0, four of T3N0, 15 of T3N1, four of T4N0, and eight of T4N1. Following chemoradiotherapy, CR was obtained in 18 (54.5%): seven cCR and 11 uCR. Eleven were partial response (PR) (33.3%), while three were stable disease (SD) and one was progressive disease (PD). High frequency USP (20 MHz) was able to detect tumor disappearance and restoration of the esophageal wall. One-year survival rates among CR (cCR + uCR), PR and SD + PD were 100%, 70% and 0%, respectively. A significant difference in survival was evident among CR, PR and SD + PD (P < 0.001). Three-year survival rates between cCR and uCR were 100% and 40%, respectively. A significant difference in survival was evident between cCR and uCR (P < 0.001). In seven cases of uCR, local recurrence and distant metastasis appeared within 1 year, and five died of disease progression. Not one cCR case has relapsed. Conclusion: USP, which can be accomplished with a standard endoscopy, including biopsy, in one procedure, is a useful method for objectively assessing the response to chemoradiotherapy in patients with locally advanced esophageal cancer.