Role of 18F-FDG PET/CT in assessment of esophageal cancer treated by neoadjuvant chemoradiotherapy

Abstract

Esophageal cancer is a serious and aggressive malignancy. Males are more affected than females. It ranks eighteenth among newly occurring cancers in the U.S. It also ranks as the tenth leading cause of cancer death. The majority of patients with esophageal cancer will have locally advanced disease at diagnosis. In an attempt to downstage tumors, achieve better local tumor control, and improve outcome, preoperative chemotherapy and radiotherapy have been subjected to multiple clinical trials. Assessment of therapeutic response has traditionally been performed with CT and with endoscopic gastroduodenoscopy and endoscopic US. However, the extensive tumor necrosis and fibrosis that follow chemotherapy and radiation therapy have made it difficult to evaluate the extent of residual malignancy by using these methods,18F-FDG PET is believed to be more informative for the evaluation of treatment response. Most studies assessing response to neoadjuvant therapy for esophageal cancer (3-6 weeks after completion of neoadjuvant therapy)have shown that 18F-FDG PET signal after neoadjuvant therapy correlates with histopathological response. The SUVmax is more robust because it is more reproducible, being less affected by the size and placement in the ROI. However, SUVmax is highly dependent on the statistical quality of the images and the size of the maximal pixel. In our study, the relative change in SUVmax between baseline and post-CRT PET/CT studies was calculate