Editing Sigmoidoscopy (section)

==Benefits==
Several studies have shown the potential benefits of sigmoidoscopy in detecting colorectal cancer.

In a 2009 Norwegian study, results were somewhat inconclusive at seven years.<ref name="Hoff-2009">{{cite journal |doi=10.1136/bmj.b1846 |title=Risk of colorectal cancer seven years after flexible sigmoidoscopy screening: Randomised controlled trial |year=2009 |last1=Hoff |first1=G. |last2=Grotmol |first2=T. |last3=Skovlund |first3=E. |last4=Bretthauer |first4=M. |journal=BMJ |volume=338 |pages=b1846 |pmid=19483252 |author5=Norwegian Colorectal Cancer Prevention Study Group |pmc=2688666}}</ref>

<blockquote>We found a trend towards reduced mortality from colorectal cancer for both total colorectal cancer mortality (27% reduction) and rectosigmoidal cancer mortality (37%), but this was not statistically significant in intention to screen analysis. Corresponding reductions in mortality among attenders (that is, the people actually screened, instead of just the ones in the group to be screened—this data set may include selection bias) were 59% and 76%, both statistically significant compared with the control group[.]<ref name="Hoff-2009" /></blockquote>

The study saw no detectable difference in all-cause mortality.

A 2010 British study<ref>{{cite journal |pmid=20430429 |year=2010 |last1=Atkin |first1=WS |last2=Edwards |first2=R |last3=Kralj-Hans |first3=I |last4=Wooldrage |first4=K |last5=Hart |first5=AR |last6=Northover |first6=JM |last7=Parkin |first7=DM |last8=Wardle |first8=J |last9=Duffy |first9=SW |last10=Cuzick |first10=Jack |title=Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: A multicentre randomised controlled trial |volume=375 |issue=9726 |pages=1624–33 |doi=10.1016/S0140-6736(10)60551-X |journal=The Lancet|display-authors=8 |author11=UK Flexible Sigmoidoscopy Trial Investigators |s2cid=15194212 |doi-access=free }}</ref> showed sigmoidoscopy reduced "overall colorectal cancer incidence and mortality by 31 percent", and "incidence of cancer in just the lower part of the colon (or distal colon) was reduced by approximately 50 percent for those who underwent screening compared with those in the control group."<ref>NCI [http://www.cancer.gov/clinicaltrials/results/sigmoidoscopy0510 summary] {{webarchive|url=https://web.archive.org/web/20110607002456/http://www.cancer.gov/clinicaltrials/results/sigmoidoscopy0510 |date=2011-06-07 }}  (accessed June 1, 2011)</ref>
Overall colon-cancer mortality was reduced by 43% (thus preventing one cancer per 200 screenings, and one cancer death per 500 screenings).  The study also showed that the effect was persistent—a single sigmoidoscopy reduced cancer rates for the length of the 11-year study.