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Examination of the lower colon using a sigmoidoscope, inserted into the rectum. A sigmoidoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. Also called proctosigmoidoscopy.

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(Source: NIH - National Cancer Institute)

What works? Research summarized

Evidence reviews

Screening for Colorectal Cancer: An Updated Systematic Review [Internet]

We conducted a systematic review of five key questions to assist the U.S. Preventive Services Task Force (USPSTF) in updating its 2002 recommendation for colorectal cancer (CRC) screening in average-risk adults aged 50 years or older using home fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), FS and FOBT, colonoscopy, or double-contrast barium enema (DCBE). Key questions for this updated review primarily focused on evidence gaps from the previous review: 1) the accuracy (one-time test performance characteristics) and potential harms of newer CRC screening tests—fecal immunochemical tests (FIT), high-sensitivity FOBT, fecal DNA testing, and CT colonography (CTC)—as possible substitutes for currently recommended CRC screening modalities; 2) updating of evidence on the impact of CRC screening on mortality and to estimate the accuracy and harms of colonoscopy and FS in the community setting. A concurrent decision analysis done by others addressed screening program performance, and compared the life-years gained using different CRC screening tests, test intervals, and stopping ages.

Systematic review and meta-analysis of the evidence for flexible sigmoidoscopy as a screening method for the prevention of colorectal cancer

BACKGROUND: Colorectal cancer is a significant cause of death. Removal of precancerous adenomas, and early detection and treatment of cancer, has been shown to reduce the risk of death. The aim of this review and meta-analysis was to determine whether flexible sigmoidoscopy (FS) is an effective population screening method for reducing mortality from colorectal cancer.

Effect of flexible sigmoidoscopy-based screening on incidence and mortality of colorectal cancer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Randomized controlled trials (RCTs) have yielded varying estimates of the benefit of flexible sigmoidoscopy (FS) screening for colorectal cancer (CRC). Our objective was to more precisely estimate the effect of FS-based screening on the incidence and mortality of CRC by performing a meta-analysis of published RCTs.

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Summaries for consumers

Bowel cancer: Sigmoidoscopy and colonoscopy

In a colonoscopy, the entire large intestine is examined for bowel polyps and areas of abnormal tissue. These can then be removed straight away during the procedure. Sigmoidoscopy is similar, but only involves part of the large intestine.In Germany, bowel cancer screening is intended for people between the ages of 50 and 75 with an average risk of bowel cancer. The costs of guaiac fecal occult blood tests and colonoscopies are covered by statutory health insurance in Germany.Sigmoidoscopy is not offered as part of bowel cancer screening and also not covered by statutory insurance funds for this purpose. But studies have shown that sigmoidoscopy screening can indeed lower the risk of getting bowel cancer or dying of it. These studies also help to get an idea of the benefits of colonoscopies.

Comparison of two methods used in screening for colorectal cancer

Cancer in the large intestine (colon) and rectum is one of the most frequent cancers in developed countries. The disease develops from benign lesions over a time span of about 10 years. If the lesion has turned into cancer, the prognosis is far better if the disease is detected at an early stage. Screening and detection for early cancers and benign precursors may therefore reduce the number of deaths caused by this disease. Cancers and benign precursors may bleed, and the blood can be detected in the stool by specific tests, the so‐called faecal occult blood tests (FOBT). If the test is positive (that is blood is detected), the person will be offered a colonoscopy to find the source of bleeding. Unfortunately, FOBT fails to discover a considerable number of cancers and precursor lesions. Therefore, endoscopic examination of the rectum and lower large intestine (the sigmoid colon) has been advocated (called flexible sigmoidoscopy). Flexible sigmoidoscopy is performed with a flexible instrument inserted through the anus and introduced about 50 centimetres into the lower large intestine after cleansing with a small enema. This allows direct visual inspection of the interior wall of the intestine, and benign lesions and malignant tumours may be detected. Benign lesions may be removed in the same session without anaesthesia and without any discomfort for the patient, and a follow‐up colonoscopy may be offered.

Recognizing warning signs of bowel cancer

Because bowel cancer does not cause obvious problems for a long time, it is only rarely detected at an early stage. But recognizing warning signs and taking them seriously as soon as possible can save precious time for people who are especially at risk. The earlier the cancer is discovered, the more successful treatment is likely to be.Noticing the following warning signs does not necessarily mean you have cancer though. On the contrary, in most cases they are caused by something harmless or another illness, such as enlarged hemorrhoids or an intestinal inflammation.The warning signs of bowel cancer areBlood in the stool or anal bleedingAnal mucus secretionChange in bowel habits over several weeks (for example constipation or diarrhea)The feeling of not being able to empty your bowels properlyPains or cramps in the abdomen (belly) or around the anusUnintentional weight lossAnemia due to low iron levels in the blood, leading to tiredness and weaknessHowever, bowel cancer is only rarely the cause of these problems, especially in people under 40 years old.

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More about Sigmoidoscopy

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Also called: Proctosigmoidoscopy

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