ABSTRACT
AIM: Endorectal ultrasonography (ERUS) and high-resolution Magnetic Resonance Imaging (HR-MRI) are two frequently used techniques for the preoperative staging of rectal cancer to offer proper neoadjuvant or surgical treatment. Because tumor restaging after neoadjuvant therapy using ERUS and HR-MRI remains challenging the aim of this study is to determine which of the two imaging methods used in restaging rectal cancer has the highest accuracy. MATERIAL AND METHODS: We included patients with rectal cancer who underwent ERUS and HR-MRI scans before and after neoadjuvant chemo-radiotherapy (n-CRT). The n-CRT was followed by imagistic restaging at 6 weeks after the last therapy session and by surgical resection. The pathology stage from the surgical sample was compared with the HR-MRI and ERUS restaging. RESULTS: Fifty-four patients underwent n-CRT and 47 were restaged by both ERUS and HR-MRI. ERUS was accurate in tumor restaging after n-CRT in 29 cases (61.7%) and HR-MRI in 32 cases (68%). Regarding lymphatic node status, ERUS was accurate for 34 patients (72.3%) and had an overall rate of over-staging of 12.8% and 14.9% of under-staging. HR-MRI was accurate for 30 patients (63.8%) in restaging the lymph nodes after n-CRT and had an overall rate of over-staging of 25.5% and 10.7% of under-staging. CONCLUSION: Restaging rectal cancer after n-CRT remains difficult because of radiotherapy tissue alteration, which results in low diagnostic accuracy for both methods. KEY WORDS: Endorectal Ultrasonography (ERUS), High-Resolution Magnetic Resonance Imaging (HR-MRI), Neoadjuvant Chemo-Radiotherapy, Rectal Cancer Restaging.
