Rectal MRI Interpretation After Neoadjuvant Therapy

Abstract

In recent years, several key advances in the management of locally advanced rectal cancer have been made, including the implementation of total mesorectal excision as the standard surgical approach; use of neoadjuvant chemoradiotherapy in selected patients with a high risk of local recurrence, and finally, adoption of organ preservation strategies, through either local excision or nonoperative management in selected patients with clinical complete response following neoadjuvant chemoradiotherapy. This review aims to shed light on the role of rectal MRI in the assessment of treatment response after neoadjuvant therapy, which is especially important given the growing feasibility of nonoperative management. First, an overview of current neoadjuvant therapies and response assessment based on digital rectal examination, endoscopy, and MRI will be provided. Second, the use of a high‐quality restaging rectal MRI protocol will be presented. Third, a step‐by‐step approach to assessing treatment response on restaging rectal MRI following neoadjuvant treatment will be outlined, acknowledging challenges faced by radiologists during MRI interpretation. Finally, research related to response assessment will be discussed. Level of Evidence 4 Technical Efficacy Stage 3

Split scar sign to predict complete response in rectal cancer after neoadjuvant chemoradiotherapy: systematic review and meta-analysis

“…By 2030, its incidence is expected to increase to up to 2.2 million new cases and more than 1 million deaths yearly [ 1 ]. Current therapeutic strategies for rectal cancer are guided by initial staging, which depends upon local extension assessed by magnetic resonance imaging (MRI) [ 2 ]. Standard treatment of locally advanced rectal cancer (LARC) involves neoadjuvant chemoradiotherapy (CRT) followed by surgical resection through total mesorectal excision (TME) [ 3 ].…”

Medical Radiology: Current Progress

“…The normalization of the rectal wall is appreciable in 5% of cases [49]. Some studies have proposed an analog to histopathological tumor regression grade (TRG), which has been named mrTRG, first of all by the Magnetic Resonance Imaging and Rectal Cancer European Equivalence Study (MERCURY) [50] (Figure 7).…”

Interpretation of Rectal MRI after Neoadjuvant Treatment in Patients with Rectal Cancer

“…직장 MRI의 확산강조영상의 해석에 있어 주의할 점으로는 크게 1) 자화율 허상(susceptibility artifact), 2) T2 shine through, 3) T2 dark through 현상이 있다( 33 ). 먼저 직장 내 공기로 인한 자화율 허상이 병변의 평가를 어렵게 할 수 있으므로 가능한 자화율 허상이 적은 영상을 획득하는 것이 중요하다.…”