Predicting response to neoadjuvant therapy in esophageal cancer

Despite improvements in preoperative staging, surgical techniques and postoperative care, the 5-year survival rate of patients with locally advanced esophageal cancer remains only approximately 15-40%. Therefore, multimodality treatment options have been widely promoted in the therapy of this malignant disease. However, recent meta-analyses evaluating randomized trials of neoadjuvant therapy protocols prior to surgery for patients with advanced esophageal cancer showed only modest improvement of survival for the whole treatment group. Among these patients, those with excellent histopathologic response seem to benefit greatly from neoadjuvant regimens. Therefore, predictive markers to allow individualization of multimodality therapy in locally advanced esophageal cancer are needed to identify those who will benefit the most. Unfortunately, there is still a great lack of markers for response assessment in patients with esophageal cancer undergoing multimodality therapy. Endoscopy, endoscopic biopsies, computed tomography and endoscopic ultrasound do not seem to provide reliable information for assessing the response to neoadjuvant therapy. Whether (18)F-fluorodeoxyglucose-PET can effectively characterize responders in neoadjuvant therapy protocols remains controversial. Finally, although results of mostly retrospective studies on molecular factors for response assessment in esophageal cancer patients are promising, these markers do not yet provide a reliable and cost-effective molecular tool for utilization in clinical practice.