title: Magnetic resonance colonography for colorectal cancer screening in patients with Lynch syndrome gene mutation.
abstract: Lynch syndrome gene carriers have a 50-80% risk of colorectal cancer (CRC). Current guidelines recommend yearly colonoscopy, with associated procedure-related risks. Magnetic resonance colonography (MRC) was evaluated as a non-invasive alternative for CRC screening in this high-risk population. Adult Lynch syndrome gene carriers underwent both screening procedures on the same day. MRI radiologists read the scans and rated image quality. Endoscopists performed colonoscopy unaware of MRC findings until after procedure completion. If lesions were detected, their number, size and location were noted. Post-procedure, patients compared discomfort and inconvenience of MRC and colonoscopy on a visual analogue scale. Thirty patients were recruited. 83% of the MRC scans were of adequate to good quality. MRC detected three lesions in three patients (70, 36, 17 mm). All 3 were independently detected on colonoscopy, excised and found to be CRC. MRC failed to detect a 3 mm CRC found on colonoscopy. CRC prevalence was 13%. Colonoscopy detected a further 30 polyps, all <10 mm. Of these, 17 were hyperplastic polyps and 10 normal mucosa. Colonoscopy had a false positive rate of 32% as defined by histology. MRC failed to detect any polyp <10 mm. Mean patient discomfort scores were 20% for MRC and 68% for colonoscopy, P = 0.003. Mean patient inconvenience scores were 54% for MRC and 52% for colonoscopy, P = 0.931. MRC was reliable in detecting large polyps, potentially CRC. However MRC currently has poor sensitivity in detecting small polyps, limiting its utility in adenoma screening at this time. MRC was associated with less discomfort than CC.
authors.affiliation: Department of Gastroenterology and Clinical Nutrition Service, Royal Melbourne Hospital, Grattan Street, Parkville, VIC 3052, Australia. ejlim@rocketmail.com
authors.forename: Eu Jin
authors.initials: EJ
authors.lastname: Lim
authors.forename: Christopher
authors.initials: C
authors.lastname: Leung
authors.forename: Alex
authors.initials: A
authors.lastname: Pitman
authors.forename: Damien L
authors.initials: DL
authors.lastname: Stella
authors.forename: Gregor
authors.initials: G
authors.lastname: Brown
authors.forename: Masha
authors.initials: M
authors.lastname: Slattery
authors.forename: Kaye
authors.initials: K
authors.lastname: Marion
authors.forename: Finlay
authors.initials: F
authors.lastname: Macrae
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000230:Adenocarcinoma / Q000175:diagnosis / Q000235:genetics; D000236:Adenoma / Q000175:diagnosis / Q000235:genetics; D000328:Adult; D000368:Aged; D003111:Colonic Polyps / Q000473:pathology; D023881:Colonography, Computed Tomographic; D003113:Colonoscopy; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis* / Q000235:genetics*; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D010865:Pilot Projects; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein