Comparison of Magnetic Resonance Imaging (MRI) and Endoluminal Endoscopic Ultrasound (EUS) for Restaging Rectal Cancer After Neoadjuvant Chemotherapy

Authors

Judy Sheffeh
Amr Aref, Corewell Health East
Mohammed Barawi
Amer Alame, Corewell Health East
Amer Zeni, Corewell Health East
Ernesto R. Drelichman
Jasneet S. Bhullar

Document Type

Conference Proceeding

Publication Date

5-12-2025

Abstract

Purpose/Background: Given the high incidence and mortality of rectal cancer, accurate staging and restaging are crucial for guiding optimal interventions. However, no consensus exists on the best imaging modality for restaging after neoadjuvant chemoradiotherapy. This study aims to compare MRI and EUS in the restaging of rectal cancer following neoadjuvant chemoradiotherapy.

Methods/Interventions: We conducted a prospective observational study and enrolled patients with rectal cancer. EUS and MRI were performed at diagnosis for initial staging and repeated after neoadjuvant chemotherapy and chemoradiotherapy for restaging. A total of 43 patients were enrolled, with 25 patients (10 males, 15 females) with rectal cancer who completed neoadjuvant chemoradiotherapy meeting the study's objectives. Histopathological staging after surgery served as the reference for comparing the accuracy of restaging with EUS and MRI. The median time between the completion of neoadjuvant chemoradiotherapy and surgery was 15 weeks.

Results/Outcomes: Among the 25 patients, 12 underwent total mesorectal excision (TME), and 13 underwent local excision (LE). In the TME group, EUS matched the T stage of surgical histopathology in 2 out of 12 cases, while MRI matched in 3 out of 12. For N staging, EUS matched the surgical histopathology in 10 out of 12 cases, and MRI matched in 9 out of 12.
In the LE group, EUS matched the T stage in 11 out of 13 cases, and MRI also matched in 11 out of 13.

Conclusion/Discussion: MRI and EUS show similar accuracy in restaging local disease after neoadjuvant chemoradiotherapy, particularly in T0 cases (patients who underwent LE). Both modalities demonstrate comparable accuracy in N staging (patients who underwent TME). However, neither modality provided significant accuracy in T staging for locally advanced disease.

Recommended Citation

Sheffeh J, Aref A, Barawi M, Alame A, Zeni A, Drelichman ER, et al. Comparison of magnetic resonance imaging (MRI) and endoluminal endoscopic ultrasound (EUS) for restaging rectal cancer after neoadjuvant chemoradiotherapy. Paper presented at: American Society of Colon and Rectal Surgeons Annual Scientific Meeting; 2025 May 10-13; San Diego, CA

Comments

Annual Scientific Meeting of the American Society of Colon and Rectal Surgeons, May 10-13, 2025, San Diego, CA