How common is blood in stool in anal cancer?

Bleeding from the anal area may appear as bright red blood on toilet paper, on the outside of stool, or in the toilet. Anal cancer can also cause a lump, discomfort, itching, a feeling of fullness, or a change in usual bowel habits. Similar bleeding is often caused by non-cancerous conditions such as haemorrhoids or a fissure, so the pattern cannot safely be used to diagnose the cause without an examination.

Make an appointment with a clinician if you notice blood in your stool or rectal bleeding, including when it seems minor or comes and goes. They can ask about your symptoms and medical history, examine the area when appropriate, and decide whether further tests are needed. Write down when the bleeding happens, changes in stool shape or frequency, pain, and any unexplained tiredness or weight change. This information can make the consultation more useful.

Get urgent help for heavy bleeding, black or sticky stools, fainting, severe weakness, severe pain, or new confusion. Seek prompt assessment if bleeding persists, becomes more frequent, or occurs with an ongoing change in bowel habit. Urgency is based on the bleeding and associated warning signs, not on trying to decide its cause at home.

Ask what may be causing the bleeding, what examination or tests are appropriate, and how soon you should receive results. Mention past bowel problems, family history of bowel or anal cancers, immune conditions, smoking, and medicines that can affect bleeding.