Repeat Positron Emission Tomography Following Neoadjuvant Chemoradiotherapy for Esophageal Adenocarcinoma
abstract
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Predicting complete pathologic response (CPR) preoperatively can significantly affect surgical decision making. There are conflicting data regarding positron emission tomography computed tomography (PET CT) characteristics and the ability of PET CT to predict pathologic response following neoadjuvant chemoradiotherapy in esophageal adenocarcinoma because most existing studies that include squamous histology have limited numbers and use nonstandardized PET CT imaging.
Objective
To determine if PET CT characteristics are associated with CPR in patients undergoing trimodality treatment for esophageal adenocarcinoma.
Design, Setting, and Participants
A retrospective medical record review was conducted at a large tertiary cancer center from a prospectively maintained database from January 1, 2005, to December 31, 2012. Inclusion criteria were patients undergoing esophagectomy for locally advanced esophageal adenocarcinoma post-neoadjuvant chemoradiotherapy with 2 standardized PET CT studies done at our institution (pre-neoadjuvant chemoradiotherapy and post-neoadjuvant chemoradiotherapy) for review. Data collected included clinical, pathologic, imaging, and treatment characteristics.
Main Outcome and Measure
The primary study outcome was the association of PET CT characteristics with histologic confirmed pathologic response.
Results
Of the total participants, 77 patients met the inclusion criteria. Twenty-two patients (28.6%) had CPR vs 55 patients (71.4%) had incomplete pathologic response. The 2 groups were similar in age, sex, race/ethnicity, comorbid conditions, Eastern Cooperative Oncology Group status, tumor grade, chemotherapy, and radiation regimen and days between the 2 PET CTs. The mean prestandardized uptake variable (SUV; 14.5 vs 11.2; P = .05), δ SUV (10.3 vs 5.4; P = .02), and relative δ SUV (0.6 vs 0.4; P = .02) were significantly higher in those with CPR vs incomplete pathologic response. Using the Youden Index, a δ SUV value less than 45% was predictive of residual disease with a positive predictive value of 91.7% (95% CI, 73-99; P < .05).
Conclusions and Relevance
To our knowledge, this is the largest study examining the role of PET CT characteristics in esophageal adenocarcinoma for patients undergoing neoadjuvant chemoradiotherapy that demonstrates that δ SUV of less than 45% is associated with patients with residual disease but not CPR. Based on the findings from our study, the current recommendation is still surgical resection regardless of the posttherapy PET SUV in the primary tumor. However, our study highlights the ability to detect patients with residual disease and the need to critically evaluate these patients for consideration of additional therapies.
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Additional Info
Disclosure statements are available on the authors' profiles:
Role of Repeat 18F-Fluorodeoxyglucose Positron Emission Tomography Examination in Predicting Pathologic Response Following Neoadjuvant Chemoradiotherapy for Esophageal Adenocarcinoma
JAMA Surg 2015 Apr 22;[EPub Ahead of Print], M Kukar, RM Alnaji, F Jabi, TA Platz, K Attwood, H Nava, K Ben-David, D Mattson, K Salerno, U Malhotra, K Kanehira, J Gannon, SN HochwaldFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
In a recent article by Kukar and colleagues, serial FDG-PET scans were evaluated for their ability to predict a pathologic complete response following chemoradiotherapy for esophageal adenocarcinoma.1 In this retrospective study, the authors examined patients with esophageal adenocarcinoma who had a baseline PET scan and a post-treatment PET scan prior to esophagectomy. Among the 77 patients who were eligible, 22 (28.6%) had a pathologic complete response with preoperative chemoradiotherapy. These patients appeared to have a higher baseline SUV on FDG-PET (14.5 vs 11.2) and a greater drop in SUV following preoperative therapy (relative decrease in SUV of 0.6 vs 0.4 for patients with an incomplete PET response); both comparisons were significant with P < .05.1
This was an important study in that it focused on a uniform patient population with esophageal adenocarcinoma, and all patients received preoperative chemoradiotherapy. However, there are some uncertainties such as whether the glucose levels prior to the FDG-PET scan were uniform, the timing of the PET scan relative to the FDG infusion, and the timing of the PET scan relative to completion of chemoradiotherapy. However, despite these uncertainties, the investigators did find that patients with a poor PET response (<45% decrease in SUV) were likely to have residual disease (predictive value, 91.7%). Not surprisingly, this cutoff did not predict pathologic complete response (positive predictive value of only 38%). This is one of several studies that demonstrate the predictive value of PET in distinguishing patients with good vs poor survival.2-6 What is yet to be determined is whether a PET non-responding patient can be salvaged with alternative therapy. This is the subject of two US national studies in esophagus and gastric cancers.
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