MRI restaging of rectal cancer: The RAC (Response–Anal canal–CRM) analysis joint consensus guidelines of the GRERCAR and GRECCAR groups - 17/03/23

Doi : 10.1016/j.diii.2023.02.002

Stephanie Nougaret ^a,^b,^⁎ , Pascal Rousset ^c, Doenja M.J. Lambregts ^d, Monique Maas ^d, Kirsten Gormly ^e,^f, Oliver Lucidarme ^g,^h, Serge Brunelle ⁱ, Laurent Milot ^j, Lionel Arrivé ^k,^l, Celine Salut ^m, Franck Pilleul ⁿ, Constance Hordonneau ^o, Guillaume Baudin ^p, Philippe Soyer ^q,^r, Vanessa Brun ^s, Valérie Laurent ^t, Celine Savoye-Collet ^u, Iva Petkovska ^v, Jean-Pierre Gerard ^w, Eddy Cotte ^x,^y, Philippe Rouanet ^z, Onofrio Catalano ^aa,^bb, Quentin Denost ^cc, Regina Beets Tan ^d, Nora Frulio ^m, Christine Hoeffel ^dd
^a Department of Radiology IRCM, Montpellier Cancer Research Institute, 34000 Montpellier, France
^b INSERM, U1194, University of Montpellier, 34295, Montpellier, France
^c Department of Radiology, CHU Lyon-Sud, EMR 3738 CICLY, Université Claude-Bernard Lyon 1, 69495 Pierre-Benite, France
^d Department of Radiology, The Netherlands Cancer Institute, 1006 BE, Amsterdam, the Netherlands
^e Jones Radiology, Kurralta Park, 5037, Australia
^f University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
^g Department of Radiology, Pitié-Salpêtrière Hospital, AP-HP, 75013 Paris, France
^h LIB, INSERM, CNRS, UMR7371-U1146, Sorbonne Université, 75013 Paris, France
ⁱ Department of Radiology, Institut Paoli-Calmettes, 13009 Marseille, France
^j Department of Diagnostic and Interventional Radiology, Hôpital Edouard Herriot, Hospices Civils de Lyon, University of Lyon, 69003 Lyon, France
^k Department of Radiology, Hôpital Saint-Antoine, AP-HP, 75012 Paris, France
^l Sorbonne Université, 75013 Paris, France
^m CHU de Bordeaux, Department of Radiology, Université de Bordeaux, 33000 Bordeaux, France
ⁿ Department of Radiology, Centre Léon Bérard, Lyon, France Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, 69621, Lyon, France
^o Department of Radiology, CHU Estaing, 63000 Clermont-Ferrand, Cedex, France
^p Department of Radiology, Centre Antoine Lacassagne, 06100 Nice, France
^q Department of Radiology, Hôpital Cochin, AP-HP, 75014 Paris, France
^r Université Paris Cité, 75006 Paris, France
^s Department of Radiology, CHU Hôpital Pontchaillou, 35000 Rennes, France
^t Department of Radiology, Nancy University Hospital, Université de Lorraine, 54500 Vandoeuvre-lès-Nancy, France
^u Department of Radiology, Rouen University Hospital, 76000 Rouen, France
^v Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
^w Department of Radiotherapy, Centre Antoine Lacassagne, 06000 Nice, France
^x Department of Digestive Surgery, Hospices Civils de Lyon, Lyon Sud University Hospital, 69310 Pierre Bénite, France
^y Lyon 1 Claude Bernard University, 69100 Villeurbanne, France
^z Department of Surgery, Institut Régional du Cancer de Montpellier, Montpellier Cancer Research Institute, INSERM U1194, University of Montpellier, 34295, Montpellier, France
^aa Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
^bb Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
^cc Department of Digestive Surgery, Hôpital Haut-Lévèque, Université de Bordeaux, 33000 Bordeaux, France
^dd Department of Radiology, Hôpital Robert Debré & CRESTIC, URCA, 51092 Reims, France

^⁎Corresponding author.

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Friday 17 March 2023
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Highlights

•	The evaluation of tumor response in rectal cancer is a challenge for the radiologist.
•	The main features to evaluate can be summarized through the “RAC assessment: Response–Anal canal– Circumferential resection margin”.
•	The combination of functional and morphological tumor features on MRI helps assess rectal tumor response to neoadjuvant therapy.
•	After a near complete tumor response on MRI, another MRI evaluation at six to ten weeks is recommended to potentially propose a watch and wait approach.

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Abstract

Purpose

To develop guidelines by international experts to standardize data acquisition, image interpretation, and reporting in rectal cancer restaging with magnetic resonance imaging (MRI).

Materials and methods

Evidence-based data and experts’ opinions were combined using the RAND-UCLA Appropriateness Method to attain consensus guidelines. Experts provided recommendations for reporting template and protocol for data acquisition were collected; responses were analysed and classified as “RECOMMENDED” versus “NOT RECOMMENDED” (if ≥ 80% consensus among experts) or uncertain (if < 80% consensus among experts).

Results

Consensus regarding patient preparation, MRI sequences, staging and reporting was attained using the RAND-UCLA Appropriateness Method. A consensus was reached for each reporting template item among the experts. Tailored MRI protocol and standardized report were proposed.