Controversies in preoperative therapy in esophageal cancer: Current evidence and ongoing research

Esophageal cancer incidence is growing worldwide, especially adenocarcinomas in the western world. Outcomes overall are universally poor, with the best survival seen in earlier stages of the disease, where surgery is the mainstay of treatment. Although squamous cell cancers and adenocarcinomas of the esophagus have different etiology, clinical features, biological behavior and prognosis, earlier research studies have frequently combined the two histologies. Several trials in the past three decades have been carried out in the neoadjuvant, adjuvant and perioperative settings in attempts to improve survival further. Most of the initial studies were small and underpowered, and showed no benefit with neoadjuvant or adjuvant treatment over surgery alone. More recent well-designed trials have now established that the neoadjuvant (in squamous and adenocarcinomas) and the perioperative (in adenocarcinomas) strategies result in superior outcomes compared to surgery alone. However, the optimum neoadjuvant strategy has still not been identified, with both neoadjuvant chemotherapy and chemoradiotherapy (both followed by surgery) showing superior outcomes over surgery alone. Direct comparisons of these two neoadjuvant protocols have not shown a clear benefit of one over the other, although more trials are ongoing and may settle this debate. Future studies using personalized medicine and immunotherapy are required to evaluate their role in the management of esophageal cancers.