Diagnosing Complete Response to Preoperative Chemoradiation in Esophageal Cancer Using Dynamic Contrast-Enhanced MRI Response Criteria.

Objective: To assess the performance of novel qualitative diagnostic criteria using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to identify the pathologic complete response (pCR) of primary tumors in esophageal cancer after neoadjuvant chemoradiation (nCRT).

Materials And Methods: Patients who underwent nCRT, subsequent MRI, positron emission tomography/computed tomography (PET/CT), endoscopy, or esophagectomy for esophageal cancer between October 2021 and October 2023 were retrospectively analyzed. The DCE-MRI response of primary tumors was interpreted using five grades by thoracic radiologists as follows: G1 (compatible with CR), G2 (probable CR), G3 (probable partial response [PR]), G4 (compatible with PR), and G5 (stable or progressive disease). The performances of MRI, PET/CT, endoscopy, and their combinations in diagnosing pCR in primary tumors were calculated.

Results: A total of 52 patients (male:female, 46:6; age, 61.2 ± 8.0 years) were included. Surgical specimens revealed pCR (ypT0) in 34 patients. G1 as the MRI criterion for pCR of primary tumors yielded a positive predictive value (PPV), specificity of 100% (18/18), and low sensitivity (23.5% [8/34]). Combining G1 and G2 as the MRI criteria increased the sensitivity to 73.5% (25/34), with a specificity of 88.9% (16/18), accuracy of 78.8% (41/52), and PPV of 92.6% (25/27). Adding the DCE-MRI results (G1-2) significantly improved accuracy for both PET/CT (from 65.4% [34/52] to 80.8% [42/52], = 0.03) and endoscopy (from 55.8% [29/52] to 76.9% [40/52], = 0.005), with increase in sensitivity (from 55.9% [19/34] to 82.4% [28/34] for PET/CT-based evaluation [ = 0.008] and from 47.1% [16/34] to 82.4% [28/34] for endoscopy-based evaluation [ = 0.001]).

Conclusion: DCE-MRI-based grading shows high diagnostic performance for identifying pCR in primary tumors, particularly in terms of PPV and specificity, and enhances response evaluation when combined with PET/CT and endoscopy.