A major focus of research in oncology is to identify patients who, following induction therapy, have a complete pathologic response, presenting opportunities for novel trials, including extended therapy or non-operative approaches, in addition to identifying cohorts who are resistant to the neoadjuvant therapy. The current gold standard for determining response to CRT is pathological evaluation following surgical resection, in particular the Mandard Tumour Regression Grade (TRG) or some modification thereof. At this time, however, there is no preclinical early response or post-treatment biomarker, nor endoscopic or radiologic assessment that predicts pathologic response prior to surgical resection.The aim of this study is to determine the accuracy of CT-PET for prediction of histopathologic response and/or oncologic outcome for patients with esophageal cancer.

Inclusion Criteria:

• Locally advanced esophageal or junctional neoplasm
• Histologically confirmed adenocarcinoma or squamous cell carcinoma
• Scheduled to undergo nCRT followed by surgery as per multidisciplinary Tumor Board
• CT-PET at diagnosis of malignancy (within 2 weeks from diagnosis), performed at study Center
• CT-PET 4-6 weeks after completion of nCRT, prior to surgical resection

Exclusion Criteria:

• Incomplete data, patient lost to follow-up
• Scans performed at alternate Center

Records for all patients with locally advanced esophageal and junctional tumors undergoing potentially curative multimodal therapy between November 2008 and November 2014 will be assessed.