Pre-Chemoradiotherapy FDG PET/CT cannot Identify Residual Metabolically-Active Volumes within Individual Esophageal TumorsLu W1*, Tan Sv1,2, Chen W3, Kligerman S3, Feigenberg SJ1, Zhang H1, Suntharalingam M1, Kang M1,4 and D'Souza WD1
- *Corresponding Author:
- Wei Lu
Associate Professor of Physics
Department of Radiation Oncology
University of Maryland School of Medicine
22 South Greene Street, Baltimore
Maryland 21201, USA
E-mail: [email protected]
Received date : April 02, 2015; Accepted date : April 25, 2015; Published date : April 29, 2015
Citation: Lu W, Chen W, Kligerman S, Feigenberg SJ, Zhang H, et al. (2015) Pre-Chemoradiotherapy FDG PET/CT cannot Identify Residual
Metabolically-Active Volumes within Individual Esophageal Tumors. J Nucl Med Radiat Ther 6:226. doi:10.4172/2155-9619.1000226
Copyright: ©2015 Lu W, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited..
Objective: To study whether subvolumes with a high pre-chemoradiotherapy (CRT) FDG uptake could identify residual metabolically-active volumes (MAVs) post-CRT within individual esophageal tumors. Accurate identification will allow simultaneous integrated boost to these subvolumes at higher risk to improve clinical outcomes.
Methods: Twenty patients with esophageal cancer were treated with CRT plus surgery and underwent FDG PET/CT scans before and after CRT. The two scans were rigidly registered. Seven MAVs pre-CRT and four MAVs post-CRT within a tumor were defined with various SUV thresholds. The similarity and proximity between the MAVs pre-CRT and post-CRT were quantified with three metrics: fraction of post-CRT MAV included in pre-CRT MAV, volume overlap and centroid distance.
Results: Eight patients had no residual MAV. Six patients had local residual MAV (SUV ≥2.5 post-CRT) within or adjoining the original MAV (SUV ≥2.5 pre-CRT). On average, less than 65% of any post-CRT MAVs was included in any pre-CRT MAVs, with a low volume overlap <45%, and large centroid distance >8.6 mm. In general, subvolumes with higher FDG-uptake pre-CRT or post-CRT had lower volume overlap and larger centroid distance. Six patients had new distant MAVs that were determined to be inflammation from radiation therapy.
Conclusions: Pre-CRT PET/CT cannot reliably identify the residual MAVs within individual esophageal tumors. Simultaneous integrated boost to subvolumes with high FDG uptake pre-CRT may not be feasible.