Chapter 1
Chapter 1
MRI to guide clinical management of rectal cancer: updated consensus recommendations from the European Society of Gastrointestinal and Abdominal Radiology: PART TWO-Restaging and response evaluation
Abstract
Objectives To provide up-to-date consensus recommendations on the acquisition, interpretation and reporting of MRI for restaging and response evaluation of rectal cancer after neoadjuvant treatment.
Materials and methods A panel of twenty-six abdominal imaging experts from the European Society of Gastrointestinal and Abdominal Radiology participated in an online consensus process, led by three independent non-voting chairs. The process adhered to an adapted version of the RAND-UCLA Appropriateness Method. A total of one hundred twenty-six items were scored (twenty-two general, fifty-five on primary staging, and forty-nine on restaging after neoadjuvant treatment), and classified using a cut-off of eighty percent to establish consensus.
Results Consensus was reached for one hundred twenty-one items (ninety-six percent), from which recommendations regarding hardware, patient preparation, image acquisition protocols, criteria for image interpretation, and MRI reporting were constructed. The current manuscript addresses the results related to restaging after neoadjuvant treatment. Only one out of forty-nine restaging items did not reach consensus. Compared to the previous guideline editions, updated and more detailed recommendations were established on how to assess fibrosis after neoadjuvant therapy, how to restage in the setting of organ preservation, the use of tumour regression grading systems, response assessment in mucinous tumours, evaluation of mesorectal fascia involvement and presence of extramural venous invasion after neoadjuvant treatment, and how to deal with nodal response for defining the ycN-category after treatment.
Conclusions These updated expert consensus recommendations serve as clinical guidelines for the restaging of rectal cancer after neoadjuvant treatment using MRI. Recommendations for primary staging are addressed in a separate publication.
Key Points Question Since the last European Society of Gastrointestinal and Abdominal Radiology rectal imaging guideline update, the rectal cancer treatment landscape has further evolved, necessitating updates to the existing guidelines.
Introduction
Introduction
In twenty thirteen, the European Society of Gastrointestinal and Abdominal Radiology published its first consensus recommendations on MRI for staging rectal cancer. An updated version was published in twenty eighteen, introducing structured template reports for primary (baseline) staging and restaging after neoadjuvant treatment, including detailed recommendations on lymph node staging and the use of diffusion-weighted imaging. The guideline has now undergone another update, which is divided into two separate publications. The first part contains recommendations for MRI acquisition, interpretation and reporting during primary staging and is presented in a separate publication. The current paper (part two) addresses recommendations for restaging and response evaluation after neoadjuvant treatment. This guideline does not comprise recommendations on multidisciplinary management and follow-up during organ preservation.