Does rectal cancer cause change in bowel habits?

Change in Bowel Habits is a very common presentation of Rectal Cancer. A tumour in the rectum can narrow the passage or irritate its lining, changing how stool moves through the lower bowel.

Changes may include new constipation, looser stools, alternating constipation and diarrhoea, narrower stools, urgency, or a feeling that the bowel has not emptied. These symptoms can also arise from conditions such as haemorrhoids, infection, medication effects, or irritable bowel syndrome. A persistent or progressive change needs assessment rather than self-diagnosis.

Arrange a medical review if a new bowel pattern continues, keeps returning, or comes with rectal bleeding, abdominal discomfort, tiredness, or unexplained weight loss. The clinician may ask when the change began, examine you, arrange blood tests, and consider bowel investigations such as colonoscopy. Keep a brief record of stool frequency, appearance, urgency, bleeding, and medicines.

Seek urgent help for heavy or ongoing rectal bleeding, black stools, severe abdominal pain, repeated vomiting, a swollen abdomen, faintness, or inability to pass stool and gas. These signs can indicate bleeding or bowel blockage and should not wait for a routine appointment.

Ask which explanations fit your symptoms, whether you need bowel testing, what preparation is required, and which changes should prompt faster contact.