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Early detection of colorectal cancer with flexible sigmoidoscopy

This fact box will help you to weigh the benefits and harms of early detection of colorectal cancer with flexible sigmoidoscopy. The information and numbers are based on the best scientific evidence currently available.

This fact box was developed by the Harding Center for Risk Literacy.

What is colorectal cancer?

Colorectal cancer occurs in the inner wall of the large intestine and usually starts with precancerous lesions (polyps). Polyps are benign growths of tissue in the mucous membrane of the large intestine that may grow into colorectal cancer.

What is early detection of colorectal cancer with flexible sigmoidoscopy?

Early detection (screening) targets people who do not show symptoms of a particular disease (here, colorectal cancer). The aim is to detect and treat colorectal cancer earlier.

During a flexible sigmoidoscopy, the last 60 centimeters of the large intestine are examined with an endoscope (sigmoidoscope). The endoscope makes it possible to view the inner wall of the intestine and detect any abnormalities. Furthermore, potentially cancerous polyps can be removed directly during a sigmoidoscopy.

Who might consider a flexible sigmoidoscopy?

A sigmoidoscopy for early detection of colorectal cancer is not covered by statutory health insurance in Germany.

What are the alternative options?

Other forms of colorectal cancer screening that are covered by statutory health insurance are the fecal occult blood test (FOBT) for people aged 50 years and older, and colonoscopy for people aged 55 years and older [3].

Fact box_sigmoidoscopy_EN

What does the fact box show?

The fact box shows the benefits and harms of the screening with flexible sigmoidoscopy for people aged 50 years and older who either did or did not participate in screening.

The table may be read as follows:

7 out of every 1,000 people without screening died from colorectal cancer within 10 years. In the same time period, 5 out of every 1,000 people with screening died from colorectal cancer.

The numbers in the fact box are rounded. The data on colorectal cancer mortality, diagnoses, and complications were reported in four studies with about 450,000 participants [1]. The numbers on pain are based on questionnaires from about 40,000 participants [2].

What other aspects should be considered?

Screening did not affect the total number of deaths when all potential causes of death are considered. About 244 out of every 1,000 people died in total, independent of whether they were screened. This means that the studies showed no evidence of flexible sigmoidoscopy saving one life over a time period of at least 10 years.

Do the results provide proof (evidence) for the benefits and harms of the screening with flexible sigmoidoscopy?

Overall, the evidence is of moderate quality. Further research might change the results.

Last update

November 2016

Sources

Information within the fact box was obtained from the following sources:

[1] Fitzpatrick-Lewis D, Ali MU, Warren R, et al. Screening for colorectal cancer: a systematic review and meta-analysis. Clin Colorectal Cancer 2016;15(4):298-313. doi: 10.1016/j.clcc.2016.03.003.

[2] Atkin WS, Cook CF, Cuzick J, et al. Single flexible sigmoidoscopy screening to prevent colorectal can-cer: baseline findings of a UK multicentre randomised trial. Lancet 2002;359(9314):1291-300. doi: 10.1016/s0140-6736(02)08268-5.

[3] Gemeinsamer Bundesausschuss. Früherkennungsuntersuchungen im Überblick 2016 [Available from: www.g-ba.de

Fact boxes

The idea of fact boxes was developed by Lisa Schwartz and Steven Woloshin. In several studies they demonstrated that fact boxes were effective tools for informing the general public about benefits and harms of medical interventions. Read more in the overview.

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