Diffusion-weighted MRI and 18F-FDG PET/CT in assessing the response to neoadjuvant chemoradiotherapy in locally advanced esophageal squamous cell carcinoma

Abstract

Background Neoadjuvant chemoradiotherapy (nCRT) followed by surgery is a currently widely used strategy for locally advanced esophageal cancer (EC). However, the conventional imaging methods have certain deficiencies in the evaluation and prediction of the efficacy of nCRT. This study aimed to explore the value of functional imaging in predicting the response to neoadjuvant chemoradiotherapy (nCRT) in locally advanced esophageal squamous cell carcinoma (ESCC). Methods Fifty-four patients diagnosed with locally advanced ESCC from August 2017 to September 2019 and treated with nCRT were retrospectively analyzed. DW-MRI scanning was performed before nCRT, at 10–15 fractions of radiotherapy, and 4–6 weeks after the completion of nCRT. 18F-FDG PET/CT scans were performed before nCRT and 4–6 weeks after the completion of nCRT. These 18F-FDG PET/CT and DW-MRI parameters and relative changes were compared between patients with pathological complete response (pCR) and non-pCR. Results A total of 8 of 54 patients (14.8%) were evaluated as disease progression in the preoperative assessment. The remaining forty-six patients underwent operations, and the pathological assessments of the surgical resection specimens demonstrated pathological complete response (pCR) in 10 patients (21.7%) and complete response of primary tumor (pCR-T) in 16 patients (34.8%). The change of metabolic tumor volume (∆MTV) and change of total lesion glycolysis (∆TLG) were significantly different between patients with pCR and non-pCR. The SUVmax-Tpost, MTV-Tpost, and TLG-Tpost of esophageal tumors in 18F-FDG PET/CT scans after neoadjuvant chemoradiotherapy and the ∆ SUVmax-T and ∆MTV-T were significantly different between pCR-T versus non-pCR-T patients. The esophageal tumor apparent diffusion coefficient (ADC) increased after nCRT; the ADCduring, ADCpost and ∆ADCduring were significantly different between pCR-T and non-pCR-T groups. ROC analyses showed that the model that combined ADCduring with TLG-Tpost had the highest AUC (0.914) for pCR-T prediction, with 90.0% and 86.4% sensitivity and specificity, respectively. Conclusion 18F-FDG PET/CT is useful for re-staging after nCRT and for surgical decision. Integrating parameters of 18F-FDG PET/CT and DW-MRI can identify pathological response of primary tumor to nCRT more accurately in ESCC.

Comparing a PD-L1 inhibitor plus chemotherapy to chemotherapy alone in neoadjuvant therapy for locally advanced ESCC: a randomized Phase II clinical trial

“…However, due to the substantial overlap in SUVmax-DR, PET/CT was unable to discriminate pCR from MPR, as was also reported in a previous study [33]. An attempt was made to combine PET/CT with diffusion-weighted magnetic resonance imaging (DW-MRI), the results of which were encouraging, with high rates of sensitivity (90.0%) and specificity (86.0%) [34]. In another study, a model employing PET/CT images was constructed to improve the accuracy of predicting pCR, for which the AUC was 0.81, highlighting the great potential of predictive models based on radiological data [35].…”

The application of radiomics in esophageal cancer: Predicting the response after neoadjuvant therapy

“…Additionally, there are still some improvements in the process before and during statistical analysis. First, imaging professionals should continue improving imaging quality and the method of delineating the ROI, because tumor segmentation could be challenging for small lesions ( 91 ), and the extracted radiomic features may raise the question of repeatability ( 29 , 76 ). For instance, applying pre-processing before image analysis can optimize the performance of models, and proper feature selection methods can reduce the dimensionality of the generated data ( 92 ).…”

“…18F-FDG PET/CT and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have also been used to predict pCR after nCRT in patients with locally advanced ESCC. Integrating 18F-FDG PET/CT and DW-MRI parameters can more accurately identify the pathological response of ESCC primary tumors to nCRT, especially the related prediction of pCR (AUC, 0.914) ( 76 ).…”

Chemoradiotherapy with paclitaxel liposome plus cisplatin for locally advanced esophageal squamous cell carcinoma: A retrospective analysis

“…Recently, MRI has been used to evaluate the efficacy of radiotherapy and chemotherapy for esophageal cancer. 32 , 33 , 34 The recovery of the esophageal structure in the T2 phase with an ADC value ≥2.64 × 10 −3 mm 2 /s became the new CR standard, which no longer limits the thickness of the esophageal wall. The new CR standard based on MRI can effectively distinguish the prognosis of patients.…”