Interim position emission tomography-computed tomography during multimodality treatment of locally advanced esophageal cancer: a scoping review

BACKGROUND: Among cancers, esophageal cancer (EC) has one of the highest incidences and mortality in Asia. As recognized in many national guidelines, functional imaging performed with position emission tomography is recommended for patients with locally advanced disease. This review evaluated evidence for the use of fluorodeoxyglucose (FDG) interim positron emission tomography (PETint) in bimodality (chemoradiation) and trimodality (chemoradiation followed by surgery) management of locally advanced esophageal cancer (LAEC), with a focus on its prognostic and predictive value. METHODS: The MEDLINE database was searched from January 1, 2001, to January 1, 2022, as part of a scoping review. References of selected articles were manually checked to identify other articles meeting the inclusion criteria; only original articles were included, and reviews, guidelines, letters, editorials, and case reports were excluded. RESULTS: A total of 63 articles were included in this review. PET-computed tomography (PET-CT) is recognized as having a significant role in the assessment of treatment response. Studies on the predictive PETint suggest that it has a certain value, particularly for early response. Identification of poor responders or nonresponders soon after commencement of multimodality treatment allows for treatment modification. CONCLUSIONS: The scoping review indicated variable utility for the prognostic value of PETint. There is a need to improve its accuracy, which can likely be achieved through greater standardization of measurements and reporting and testing as well as combination with other promising measures of response to residual disease.