Colon Cancer Sigmoidoscopy – Indications, Procedures, Results

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 3 min read

Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

On this page7 sections

Article Summary

Colon cancer sigmoidoscopy; Colorectal sigmoidoscopy; Rectal sigmoidoscopy; Gastrointestinal bleeding - sigmoidoscopy; Rectal bleeding - sigmoidoscopy; Melena - sigmoidoscopy; Blood in stool - sigmoidoscopy; Polyps - sigmoidoscopy Sigmoidoscopy is a procedure used to see inside the sigmoid colon and rectum. The sigmoid colon is the area of the large intestine nearest to the rectum. How the Test is Performed During the test: You lie on your...

Key Takeaways

This article explains How the Test is Performed in simple medical language.
This article explains How to Prepare for the Test in simple medical language.
This article explains How the Test will Feel in simple medical language.
This article explains Why the Test is Performed in simple medical language.

Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.

Educational health guideWritten for patient understanding and clinical awareness.

Reviewed content workflowUse writer and reviewer profiles for stronger trust.

Emergency safety firstUrgent warning signs are highlighted below.

Definition

Colon cancer sigmoidoscopy; Colorectal sigmoidoscopy; Rectal sigmoidoscopy; Gastrointestinal bleeding – sigmoidoscopy; Rectal bleeding – sigmoidoscopy; Melena – sigmoidoscopy; Blood in stool – sigmoidoscopy; Polyps – sigmoidoscopy

Sigmoidoscopy is a procedure used to see inside the sigmoid colon and rectum. The sigmoid colon is the area of the large intestine nearest to the rectum.

How the Test is Performed

During the test:

You lie on your left side with your knees drawn up to your chest.
The doctor gently places a gloved and lubricated finger into your rectum to check for blockage and gently enlarge (dilate) the anus. This is called a digital rectal exam .
Next, the sigmoidoscope is placed through the anus. The scope is a flexible tube with a camera at its end. The scope is gently moved into your colon. Air is inserted into the colon to enlarge the area and help the doctor view the area better. The air may cause the urge to have a bowel movement or pass gas. Suction may be used to remove fluid or stool.
The doctor may take tissue samples with a tiny biopsy tool inserted through the scope. Heat (electrocautery) may be used to remove polyps . Photos of the inside of your colon may be taken.

Sigmoidoscopy using a rigid scope may be done to treat problems of the anus or rectum.

How to Prepare for the Test

Your health care provider will tell you how to prepare for the exam. You will use an enema to empty your bowels. This is usually done 1 hour before the sigmoidoscopy.

On the morning of the procedure, eat a light breakfast.

How the Test will Feel

During the exam you may feel:

Pressure during the digital rectal exam or when the scope is placed in your rectum.
The need to have a bowel movement.
Some bloating or cramping caused by the air or by stretching of the bowel by the sigmoidoscope.

After the test, your body will pass the air that was put into your colon.

Children may be given medicine to make them sleep lightly (sedated) for this procedure.

Why the Test is Performed

Your doctor may recommend this test to look for the cause of:

Abdominal pain
Diarrhea , constipation, or other changes in bowel habits
Blood, mucus, or pus in the stool
Weight loss that can’t be explained

This test can also be used to:

Confirm findings of another test or x-rays.
Screen for colorectal cancer or polyps .
Take a biopsy of a growth.

Normal Results

A normal test result will show no problems with the color, texture, and size of the lining of the sigmoid colon, rectal mucosa, rectum, and anus.

What Abnormal Results Mean

Abnormal results can indicate:

Anal fissures
Anorectal abscess
Blockage of the large intestine ( Hirschsprung disease )
Cancer
Colorectal polyps
Diverticulosis (abnormal pouches on the lining of the intestines)
Hemorrhoids
Inflammatory bowel disease
Inflammation or infection ( proctitis )

Risks

There is a slight risk of bowel perforation (tearing a hole) and bleeding at the biopsy sites. The overall risk is very small.

Tests & investigations

Alpha-1 Antitrypsin Blood Test - Indications, Procedure, Results78% relationship confidence Knee Joint Aspiration - Indications, Procedures78% relationship confidence Dorsal Penile Nerve Block - Indications, Contraindication73% relationship confidence Kidney Transplant - Causes, Indications, Treatment73% relationship confidence

Medicines to learn about

Debridement - Indications, Contraindications73% relationship confidence Lobectomy - Anatomy, Indications, Contraindications73% relationship confidence Superficial Peroneal Nerve - Indications, Contraindications73% relationship confidence Wound Debridement - Indications, Contraindications73% relationship confidence

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

Write when the problem started and how it changed.
Bring old prescriptions, investigation reports, and current medicines.
Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

What is the most likely cause of my symptoms?
Which danger signs mean I should go to hospital quickly?
Which tests are necessary now, and which can wait?
How should I take medicines safely and what side effects should I watch for?
When should I come for follow-up?

Tests to discuss

Vital signs: temperature, pulse, blood pressure, oxygen saturation
Basic physical examination by a clinician
CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

Rest, drink safe water, and observe symptoms carefully.
Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
Seek medical care quickly if symptoms are severe, worsening, or unusual for the patient.

OTC medicine safety

For mild pain or fever, ask a registered pharmacist or doctor before using common over-the-counter pain/fever medicines.
Do not combine multiple pain medicines without advice, especially if you have kidney disease, liver disease, stomach ulcer, asthma, pregnancy, or take blood thinners.
Do not give adult medicines to children unless a qualified clinician advises it.

Avoid these mistakes

Do not start antibiotics without a proper medical decision.
Do not use steroid tablets or injections casually for quick relief.
Do not delay emergency care because of home remedies.

Get urgent help if

Severe symptoms, confusion, fainting, breathing difficulty, chest pain, severe dehydration, or sudden weakness need urgent medical care.

Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider

Tests to discuss with doctor

Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
Relevant blood, urine, imaging, or specialist tests only after clinical assessment

Questions to ask

What is the most likely cause of my symptoms?
Which warning signs mean I should go to emergency care?
Which tests are really needed now?
Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Go to emergency care if you notice:

Severe or rapidly worsening symptoms
Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration

Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.

Step 1
Check danger signs first

If danger signs are present, seek emergency care and do not wait for online information.
Step 2
Record the symptom story

Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.
Step 3
Visit a qualified clinician

A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.
Step 4
Do only useful tests

Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.
Step 5
Follow up and return early if worse

If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips

Take a written symptom diary and all previous prescriptions/test reports.
Do not hide medicines already taken, even herbal or over-the-counter medicines.
Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

Internal learning pathway

Explore related RX articles

Related guides from RX Harun are grouped to help readers move from overview to symptoms, tests, treatment, and safe next steps.

Rx Lab Test (A - Z)

Hemoglobin A1c Test DefinitionThe hemoglobin? A1c? test—also known as glycated hemoglobin?, glycosylated hemoglobin, HbA1c?, or simply A1c—is used to measure an…
Orbital Decompression Surgery DefinitionOrbital decompression is an operation to make more room inside the eye socket. The eye socket…
Olfactory Nerve Disorders DefinitionOlfactory nerve disorders affect our sense of smell. This can impact our ability to enjoy food,…
Biological Terrain Assessment (BTA) DefinitionBiological Terrain Assessment? (BTA) is a holistic approach to understanding the health of our bodies by…
Ingrown Toenai – onychocryptosis or uunguisincarnatus DefinitionIngrown toenail, also known as onychocryptosis or uunguisincarnatus, is the most common nail problem encountered in both general…
Physical Exam HEENT DefinitionHEENT stands for “head, eyes, ears, nose, and throat?.” If someone is experiencing symptoms that affect…

Read, save, and share this guide

Article Summary

Key Takeaways

RX Patient Tools