MRI of anal cancer: assessing response to definitive chemoradiotherapy.
Anal cancer is an uncommon malignancy of the gastrointestinal tract but has a relatively good prognosis with an 80% 5-year overall survival. In this article, we review the role of MRI for assessing treatment response in anal cancer after completion of definitive chemoradiotherapy. New generation MRI scanners with optimal-phased array body coils, resulting in better signal to noise and improved contrast and spatial resolution, have contributed to high-resolution imaging in clinical practice enabling visualization of relevant anatomy including the sphincter complex, adjacent structures, mesorectal and pelvic lymph nodes with a diameter down to 2 mm. Multiplanar, high-resolution T2-weighted and diffusion-weighted sequences have a role in initial locoregional staging of anal SCC, assisting radiotherapy planning, as well as in assessing response to treatment and treatment-related complications.
Department of Radiology, Guy's & St Thomas' NHS Foundation Trust, Imaging 2, Level 1, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Road, London, SE1 7EH, UK, sgty76@gmail.com.
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D001005:Anus Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000628:therapy*; D059248:Chemoradiotherapy; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008279:Magnetic Resonance Imaging; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D016896:Treatment Outcome