Esophageal cancer is the 6th most common cause of cancer deaths in the world. Since the development of neoadjuvant chemoradation (nCRT) the prognosis of esophageal cancer has improved greatly. Therefore, nCRT with subsequent surgery has become the standard of care in the Netherlands. Currently, all patients that are treated with curative intent undergo surgery regardless of their response to nCRT. However, in 29% of patients no microscopic residual disease is found in the resection specimen after nCRT, meaning a pathological complete response (pCR) is achieved. Theoretically, these pathological complete responders can be excluded from surgery, avoiding the substantial morbidity that is associated with this procedure. However, current diagnostic strategies fall short to confidently identify these pathological complete responders. 

Previous studies using imaging techniques to assess the response to nCRT have been promising. With 18F-FDG-PET-CT (PET-CT) a sensitivity of 67% and a specificity of 68% was achieved. With diffusion-weighted MRI (DW-MRI) a sensitivity of 100%,  a specificity of 75%, a positive predictive value  of 94% and a negative predictive value of 100%, was found. Using dynamic contrast-enhanced MRI (DCE-MRI) it was possible to accurately differ between complete responders and patients that did not respond to nCRT. 

Although promising, none of the aforementioned techniques have proven to be adequate enough to use separately in identifying pathologic complete responders. Therefore, the aim of this study is to develop a multiparametric prediction model that predicts the probability of pathologic complete response to nCRT in esophageal cancer by integrating DW-MRI and DCE-MRI in conjunction with 18F-FDG PET-CT scans acquired prior to, during and after administration of nCRT.

Pathological response grading after neoadjuvant chemoradation in esophageal cancer.
Reference: (Gillham, Reynolds, & Hollywood, 2007)