European Journal of Epidemiology (2018) 33:773 https://doi.org/10.1007/s10654-018-0416-6(0123456789().,-volV)(0123456789().,-volV) CORRESPONDENCE 1,2 1,2,3 4,5 • • Magnus Løberg Mette Kalager Geir Hoff Received: 15 May 2018 / Accepted: 25 May 2018 / Published online: 30 May 2018 Springer Science+Business Media B.V., part of Springer Nature 2018 We have read the article by Niedermaier et al.  with however, there was no difference in the long-term great interest. This is a modelling study aiming to estimate screening effect between the two groups: The incidence of the sensitivity and speciﬁcity of a combined strategy of colorectal cancer was most reduced in the sigmoidoscopy sigmoidoscopy and fecal immunochemical test (FIT) only group, while the mortality of colorectal cancer was screening to detect colorectal neoplasia. To inform the most reduced in the combined strategy group. model, the authors performed a meta-analysis of studies We ﬁnd it worrying that the authors selectively have that have evaluated the site-speciﬁc FIT sensitivity, with referred to the NORCCAP ﬁndings supporting their view. colonoscopy as the gold standard. They have ignored to mention that there was no difference An obvious limitation with sigmoidoscopy screening is between the groups in the detection rates of any adenoma, the low sensitivity in the proximal colon, both for early advanced adenoma and cancer at screening, and that the detection of cancer, and for detection and removal of intention-to-screen analysis showed that colorectal cancer adenomas. A way to mitigate this limitation, could be to incidence was reduced in the sigmoidoscopy only group, add a FIT to the sigmoidoscopy screening, and thus try to but not in the combined strategy group. increase the detection rate of proximal cancers and ade- We are surprised to see that Niedermaier et al. put more nomas through increased referral to follow-up faith in their model than a large, well-designed randomized colonoscopy. controlled trial with sufﬁcient follow-up to capture patient The idea described above is not new: In the Norwegian important outcomes, such as colorectal cancer incidence Colorectal Cancer Prevention (NORCCAP) trial , indi- and mortality. This is in stark contrast to the GRADE viduals in the screening arm were randomized to screening system , where evidence from randomized trials are with sigmoidoscopy or a combination of sigmoidoscopy ranked above observational studies, and where models are and a once-only FIT (combined strategy). Surprisingly, the typically considered as low-quality evidence. combined strategy was less successful than anticipated, even though attendance rate was comparable in the two groups (combined strategy 61%, sigmoidoscopy only References 65%). During screening and follow-up colonoscopy, there were no differences in detection of any adenoma, advanced 1. Niedermaier T, Weigl K, Hoffmeister M, Brenner H. Diagnostic adenoma or cancer between the groups. More importantly, performance of ﬂexible sigmoidoscopy combined with fecal immunochemical test in colorectal cancer screening: meta-analysis and modeling. Eur J Epidemiol. 2017;32(6):481–93. & Magnus Løberg 2. Holme O, Loberg M, Kalager M, et al. Effect of ﬂexible email@example.com sigmoidoscopy screening on colorectal cancer incidence and mortality: a randomized clinical trial. JAMA. 2014;312:606–15. Clinical Effectiveness Research Group, Institute of Health 3. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso- and Society, University of Oslo, Postbox 1089, Coello P, et al. GRADE: an emerging consensus on rating quality 0318 Blindern, Oslo, Norway of evidence and strength of recommendations. BMJ. 2008;336(7650):924–6. Department of Transplantation Medicine and KG Jebsen Colorectal Cancer Research Center, Oslo University Hospital, Oslo, Norway Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA, USA Telemark Hospital, Skien, Norway Cancer Registry of Norway, Oslo, Norway
European Journal of Epidemiology – Springer Journals
Published: May 30, 2018
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