MRI of Rectal Cancer

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2 MRI of Rectal Cancer

3 Arnd-Oliver Schäfer Mathias Langer MRI of Rectal Cancer Clinical Atlas

4 Prof. Dr. Arnd-Oliver Schäfer Department of Diagnostic Radiology Freiburg University Hospital Hugstetter Straße Freiburg Germany Prof. Dr. Mathias Langer Department of Diagnostic Radiology Freiburg University Hospital Hugstetter Str Freiburg Germany ISBN: e-isbn: DOI: / Springer Heidelberg Dordrecht London New York Library of Congress Control Number: Springer-Verlag Berlin Heidelberg 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. Cover design: estudio Calamar Figueres/Berlin Printed on acid-free paper Springer is part of Springer Science+Business Media (

5 Preface Oncology in general has seen vast advancements over recent years. Improved understanding of tumor biology, multidisciplinary team decisions and an individualized therapy are cornerstones of treatment planning for cancer patients today. These developments have challenged the imaging community with ever more specific questions on tumor detection, staging and therapy control. Whereas this evolution applies to many tumor entities, rectal cancer takes an outstanding role, as it was the recognition of certain anatomical and pathological features of the disease, with the help of magnetic resonance imaging (MRI), that induced radiology not only to aid in disease management, but in fact to be a powerful engine for new concepts in rectal cancer treatment. The continuous improvement of highly specialized MRI and the groundbreaking scientific contributions of radiologists all over the world have paved the way for substantial refinements of this technique during the last decade. Consequently, dedicated imaging protocols for routine diagnostic work-up of rectal cancer patients are now available, which can guide multidisciplinary team decisions and, in combination with optimized surgery and chemoradiotherapy, lead to longer survival and a better quality of life. Besides the scientific advances, the enduring clinical success of MRI in the field of rectal cancer is highly contingent upon expertise. To this end, ongoing education and continuous training are vital. MRI of Rectal Cancer Clinical Atlas is a comprehensive yet streamlined synopsis reflecting current clinical opinions and case-based imaging features of rectal cancer. We hope it will aid radiologists and clinicians in understanding the essential aspects of rectal cancer and in incorporating this knowledge into their daily practice. Freiburg, Germany Arnd-Oliver Schäfer Matthias Langer v

6 Contents 1 Introduction: From a Surgeon s Point of View Therapeutic Options Local Excision of a Rectal Carcinoma Primary Transabdominal Resection Multimodal Therapy of Rectal Carcinoma Importance of the Circumferential Resection Margin Lymph Node Metastasis Outside the Mesorectum Surgical Consequences of a Stage T4 Rectal Carcinoma Ultralow Sphincter Preserving Anterior Resection vs. Abdominoperineal Resection Summary... 3 References Anorectal Anatomy Introduction Anatomy and Embryology of the Rectum and the Perirectal Tissues Blood Supply Lymphatic Drainage Mesorectum and Fascial Structures Anal Canal Pararectal and Para-Anal Spaces MRI of Rectal Anatomy: Important Landmarks Parietal Fascia Retrorectal Space Rectosacral Fascia Peritoneal Reflection Denonvillier s Fascia Mesorectal Fascia and Mesorectum Rectal Wall References Pathology of Rectal Cancer Introduction Preoperative Biopsy vii

7 viii Contents Histologic Classification Grading Tumor Spread Intraoperative Diagnostics Macroscopy of the Fresh Specimen Mesorectum Resection Margins Postoperative Diagnostics Macroscopy of the Fixed Specimen Histopathology Tumor Regression Molecular Pathology Conclusion References Magnetic Resonance Imaging of Rectal Cancer Introduction Technical Aspects The Basics of Rectal MRI for Local Staging Purposes Future Developments MRI for Primary Staging of Rectal Cancer Introduction T Staging N Staging Circumferential Resection Margin Negative Prognostic Factors in Rectal Cancer MRI After Neoadjuvant Chemoradiation Therapy MRI for the Detection of Recurrent Rectal Cancer Introduction Risk-Adapted Surveillance Imaging for Recurrent Colorectal Cancer Integrative Decisions in Rectal Cancer Selected Differential Diagnoses Mimicking Rectal Cancer Anal Cancer Cancer Arising from Anorectal Fistula Gastrointestinal Stromal Tumor of the Rectum Tumors of the Retrorectal Space Anorectal Giant Condyloma Acuminatum: Buschke-Loewenstein Tumor References Clinical Atlas Introduction Stage T1 Rectal Cancer Stage T2 Rectal Cancer Stage T3 Rectal Cancer Stage T4 Rectal Cancer Negative Prognostic Factors

8 Contents ix 5.7 Recurrent Rectal Cancer Unusual Metastatic Spread of Colorectal Cancer Differential Diagnosis of Rectal Cancer Postsurgical Anatomy

9 Contributors Tobias Baumann, MD Department of Diagnostic Radiology, Freiburg University Hospital, Hugstetter Strasse 55, Ulrich Theodor Hopt, MD Department of General and Visceral Surgery, Freiburg University Hospital, Hugstetter Strasse 55, Mathias Langer, MD, MBA Department of Diagnostic Radiology, Freiburg University Hospital, Hugstetter Strasse 55 Arnd-Oliver Schäfer, MD Department of Diagnostic Radiology, Freiburg University Hospital, Hugstetter Strasse 55, Martin Werner, MD Institute of Pathology, Freiburg University Hospital, Breisacher Strasse 115a, Thorsten Wiech, MD Institute of Pathology, Freiburg University Hospital, Breisacher Strasse 115a, xi

10 Introduction: From a Surgeon s Point of View Surgical therapy of rectal carcinoma: Value of imaging 1 Ulrich Theodor Hopt Surgical therapy of rectal carcinoma has advanced enormously since the 1990s. However, not only the surgical technique itself has improved; first and foremost has been the effort to adapt the radicality of the surgical approach to the individual patient. The objective is to avoid therapies that are either too aggressive or too conservative, while taking the patient s unique situation into account. A surgery that is too radical may not further increase the chance of cure, but may ultimately result in a long-lasting and severe reduction in quality of life. If the therapy regimen is too conservative, an increased rate of recurrence will result and the patient s long-term survival will be unavoidably reduced. 1.1 Therapeutic Options Surgical therapy in rectal carcinoma ranges from local transanal excision to multivisceral resection (Bretagnol et al. 2007). Modern imaging procedures allow physicians to determine which surgical procedure is best-suited for the individual patient and whether multimod al therapy is also necessary. The central goal of surgical therapy for rectal carcinoma is the prevention of local recurrence. Local recurrence results in fatal consequences for many patients and is directly linked to markedly reduced survival. Advanced rectal carcinoma frequently extends dorsally into the sacral plexus, causing severe pain. Ventral expansion may result in infiltration of the urinary bladder, seminal vesicles, prostate, uterus, and U. T. Hopt Department of General and Visceral Surgery, Freiburg University Hospital, Hugstetter Strasse 55, 79106, Freiburg, Germany ulirch.hopt@uniklinik-freiburg.de vagina; provoke the formation of a fecal fistula; or, at worst, lead to the formation of a cloaca, which is almost impossible to treat. Since total mesorectal excision was introduced as the standard surgical procedure for rectal resection, the risk of local recurrence has decreased considerably (Wibe et al. 2002). Nevertheless, in some large series, the recurrence rate ranged from 5 to 15%, depending on the location of the primary tumor (Kapiteijn et al. 2001; Sauer et al. 2004). This high rate of local recurrence also determines whether multimodal therapy is warranted in certain groups of patients. The decision as to which surgical procedure should be applied for a given patient strongly depends on a number of patient-specific factors, such as age, general condition, and competence of the sphincter apparatus. Various tumor-specific parameters are also of central importance. In addition to the histological classification of the tumor, exact oncological staging is a major prerequisite to evidence-based therapeutic decision making, including the stage of the primary tumor (T), the presence of lymph node metastasis (N), and the presence of distant metastasis (M). The evaluation of the so-called circumferential resection margin (CRM) is also of crucial importance. Today, a number of imaging procedures are available for staging purposes, which exhibit different degrees of accuracy for each aspect of rectal cancer staging. The current role of imaging for therapy decision making is discussed in this chapter. 1.2 Local Excision of a Rectal Carcinoma Local transanal excision can be performed in cases of T1 (low-risk) rectal cancers. Because magnetic resonance imaging (MRI) is not yet deemed accurate A-O. Schäfer, M. Langer, MRI of Rectal Cancer, DOI: / _1, Springer-Verlag Berlin Heidelberg